Thursday, April 30, 2009

What are Kimberlites?

Unlike most of the surface rocks in Kansas, which are sedimentary in origin, kimberlite is an igneous rock, formed from the cooling of molten magma. Igneous rocks are extremely rare in Kansas. Kimberlite is composed of at least 35% olivine, together with other minerals such as mica, serpentine, and calcite (Jackson, 1997). Geologists call it an ultrabasic rock, which means it does not contain any quartz or feldspar, the two most common rock-forming minerals. Olivine, the main mineral constituent of the rock, is an olive-green, grayish green, or brown mineral made up of magnesium, iron, and silica. In 1888, the name kimberlite was proposed for this particular rock, based upon the occurrence of these rocks in the vicinity of Kimberley, South Africa.

Large volumes of an olivine-rich rock type called peridotite occur at great depths in the earth in a layer called the mantle. At these depths (100-135 miles or 150-200 km), the combined temperature and pressure is high enough to partially melt some of the peridotite. If volatile gases, such as carbon dioxide and water, are present, they may propel the molten peridotite upwards, forming a kimberlite magma. As the hot kimberlite magma rises slowly upward into regions of lower temperature and pressure in the upper mantle and overlying crust, minerals start to crystallize and the volatile gases expand and exert increasingly higher pressures on the surrounding rocks, eventually breaking some of the surrounding rock and incorporating it into the magma. Closer to the earth's surface the internal pressures of the magma and volatile gases become so great that the kimberlite becomes explosive. Kimberlite magma can rise toward the surface at speeds estimated at up to 400 meters (1,200 feet) per second, ripping up more and more pieces from the surrounding rock, which gives the kimberlite its characteristic texture.

Wednesday, April 29, 2009

Remarkable Facts of Diamonds

All diamonds are at least 990,000,000 years old.

Many are 3,200,000,000 years old (3.2 billion years)!!!
How do we know this?
Age: from Carbon dating? NO! C-dating only works for very young carbon. You need to use other radioactive decay schemes (e.g., uranium-lead) to date inclusions in diamonds. Inclusions used for dating are around 100 microns in diameter (0.1 mm).

Diamonds are formed deep within the Earth: between 100 km and 200 km below the surface.

Diamonds form under remarkable conditions!
  • The temperatures are about 900 - 1300 C in the part of the Earth's mantle where diamonds form.
  • The pressure is between 45 - 60 kilobars. (kB)
  • + 50 kB = 150 km = 90 miles below the surface
  • + 60 kB = 200 km = 120 miles below the surface
Diamonds are carried to the surface by volcanic eruptions.

  • The volcanic magma conduit is known as a kimberlite pipe or diamond pipe.

    We find diamonds as inclusions in the (rather ordinary looking) volcanic rock known as kimberlite.

  • NOTE: The kimberlite magmas that carry diamonds to the surface are often much younger than the diamonds they transport (the kimberlite magma simply acts as a conveyer belt!).

* Diamond is made of carbon (C), yet the stable form (polymorph) of carbon at the Earth's surface is graphite.

* To ensure they are not converted to graphite, diamonds must be transported extremely rapidly to the Earth's surface.

  • It is probable that kimberlite lavas carrying diamonds erupt at between 10 and 30 km/hour (Eggler, 1989). Within the last few kilometers, the eruption velocity probably increases to several hundred km/hr.

Diamond is the hardest material.

  • Diamond is the hardest gem on the MOHS harness scale and graphite (also made from carbon atoms) is the softest! Given that both diamond and graphite are made of carbon, this may seem surprising.

  • The explanation is found in the fact that in diamond the carbon atoms are linked together into a three-dimensional network whereas in graphite, the carbon atoms are linked into sheets with very little to hold the sheets together (thus the sheets slide past each other easily, making a very soft material).

* Diamonds are found in many localities, both overseas and in the US.

Tuesday, April 28, 2009

How to Buy a Diamond?

People mark special events with sentimental gifts of jewelry. While weddings reign as the biggest diamond event, there are many small yet glorious celebrations that are honored with beautiful sparklies, too, such as new jobs, anniversaries, graduations, births…the list, happily, is endless.

So how do people learn about diamonds so they can buy, own and enjoy them with confidence? The nonprofit Gemological Institute of America (GIA), the world’s foremost authority in gems and jewelry and the creator of the famous 4Cs of diamonds offers these five tips:

Choose a qualified jeweler.
  • Select a jeweler as you would a doctor, a lawyer or any professional. Ask around. Find someone who is a trained gemologist, a GIA Graduate Gemologist or GIA Accredited Jewelry Professional, and is affiliated with a professional jewelry association.
  • GIA’s Web site offers in-depth information on diamonds, pearls and other gemstones. GIA even built a special Web site on the Four Cs. Knowing the Four Cs helps you speak the language of diamonds and communicate with jewelers.
Learn the 4Cs.
  • All diamonds are rare and no two diamonds are alike. A diamond’s quality and rarity is determined by its unique combination of characteristics of Color, Cut, Clarity and Carat Weight. The International Diamond Grading System, used around the world since its invention by GIA in the 1950s, is based on the 4Cs.

  • Carat: Diamonds are weighed in metric carats. Two carats weight about the same as a small paper clip. A carat is divided into 100 “points”, so a diamond of 50 points weighs 0.50 carats.

  • Clarity: Nearly all diamonds contain unique clarity characteristics. Flawless diamonds are exceptional and costly. Most inclusions are invisible unless magnified.

  • Color: Colorless diamonds are extremely uncommon. Most diamonds have a slight yellow or brown tint. GIA uses letters to represent colors, beginning with D (colorless) and ending at Z (light yellow or brown). “Fancy colored diamonds” come in every color imaginable, are also very unusual and have their own GIA color grading system.

  • Cut: While diamonds come in different shapes, such as round, pear or marquise, the term “cut” refers to proportion. The well-cut, balanced diamond has unbridled brilliance, sparkle and fire.
Get an independent diamond grading report.
  • A diamond grading report tells you the exact gemological quality of your diamond. Is it a natural diamond? Is it a synthetic diamond? Has it been treated and how? What are its quality ratings according to the Four Cs?
Have your diamond appraised and insured.
  • A diamond grading report describes the precise gemological quality of your diamond while an appraiser puts a monetary value to the stone. You can laser inscribe a personal message or the diamond’s unique GIA Grading Report number on the diamond’s girdle.

So, relax, do a little research, and before you know it you'll be as brilliant as diamond when it comes to diamond shopping.

Monday, April 27, 2009

Where Do Gems Form?

Gems form in many different environments in the Earth. We will examine the most common and important environments and formation processes in this lecture.

It is important to distinguish where gems are formed from where they are found.

Almost all gems are formed below the Earth's surface.

  • Some are brought to the surface through mining
  • Some are brought to the surface through earth processes (faulting, folding, large scale uplift, volcanism). These processes can move rock up from more than 400 km below the surface.

Formation Environments
  • Water near Earth's surface
  • Hydrothermal deposits
  • Pegmatites
  • Magmatic gems
  • Metamorphic gems
  • Gems of the mantle
Water near Earth's surface
Hydrothermal Deposits
Magmatic Gems

Metamorphic gems

Gems of the Mantle

Sunday, April 26, 2009

What is GIA?

GIA discovers (through GIA Research), imparts (through GIA Education), and applies (through the GIA Laboratory and GIA Instruments) gemological knowledge to the public. With 1,200 employees, the Institute’s scientists, diamond graders, and educators are regarded as the world's foremost authorities in gemology.

Internationally, the Institute has distinguished itself as the preeminent source of gemological knowledge and professionalism. The GIA Diamond Grading Report and the GIA Diamond Dossier® are considered to be the world's premier credentials of diamond quality. Many retailers provide diamond certification, however no report is as unbiased and complete as a GIA diamond grading report. Diamonds of all shapes and sizes are sent to the Institute from every corner of the globe for diamond grading and analysis.

Some famous diamonds have been graded by GIA including the Hope Diamond (45.52 carats), the Steinmetz Pink (59.60 carats), the Taylor-Burton (69.42 carats), the Allnatt (101.29 carats), the De Beers Millennium Star (203.04 carats), the Centenary (273.85 carats), and the Incomparable (407.48 carats).

GIA is the creator of the revolutionary 4Cs of diamond value (carat, color, clarity, and cut). It is also the birthplace of the International Diamond Grading System™. Today, GIA’s D-Z color-grading scale, Flawless–I3 clarity-grading scale and Excellent-to-Poor cut-grading scale are recognized by virtually every professional jeweler and savvy diamond buyer in the world.

Saturday, April 25, 2009

Diamond Care

Diamonds are remarkably durable, resistant to scratching except by another diamond, and maintain their brilliant fire extremely well. These qualities make a diamond well-suited to regular wear and are perfect for engagement and wedding rings, which are usually worn every day.

But even a diamond isn’t indestructible. It can be chipped by a sharp blow or become loose in its setting and fall out. A diamond should be worn with care.

Because diamonds tend to pick up grease and oils, they can become dirty with handling and should be occasionally wiped with a lint-free cloth. Other methods for safe cleaning include warm water, mild soap, and a soft toothbrush or a commercial cleaning solution. It is not recommended to use ultrasonic and steam cleaners.

Friday, April 24, 2009

How does pavillion depth affect a diamond's cut?

The distance from the bottom of the girdle to the culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape from the side of the stone, or leak out of the bottom. A well-cut diamond will direct more light through the crown.

Thursday, April 23, 2009

What is a Gemstone?

Gemstone is a collective term for all objects used with ornamental stones for personal adornment that possesses beauty, durability, and stability. Beauty, a quality that varies among individuals, can be based on one or any combination of: color or lack of color, luster, transparency, or enhanced optical properties due to cutting and fashioning by the lapidary. Durability is the resistance of the gemstone damage and dependent upon physical properties, such as hardness and tenacity. Tenacity is the resistance to bending and breaking, while hardness measures the resistance to scratch. Diamond cannot be scratched by any other mineral and therefore, it is a gem with high hardness; diamond has low tenacity, in part due to perfect cleavage. Nephrite jade is relatively soft for a gem, easily scratched by dust in the air, but it is composed of fibrous crystals that resist breaking and therefore, it is tough or has high tenacity. Stability refers to the gem's ability to retain color inspite of heat, light, or chemical assaults.

Of the 4,000+ known minerals, 70 possess qualifications for gemstones, but of these, only approximately 20 are commonly encountered (Hurlbut & Kammerling, 1991, p. 3). These minerals include: diamond, corundum (ruby, sapphire, star ruby and sapphire), beryl (emerald, aquamarine, morganite, goshenite, golden or heliodor), chrysoberyl (cat's eye & alexandrite), spinel, topaz, zircon, tourmaline (indicolite, rubellite, schorl, elbaite), garnet group (almandite/almandine, rhodolite, pyrope, grossular/tsavorite, spessartine, uvarovite), quartz: crystalline (rock crystal, amethyst, citrine, cairngorm or smoky, rose, aventurine, tiger's-eye, rutilated), quartz: cryptocrystalline (chrysoprase, carnelian, sard, bloodstone, agate, onyx, jasper, agatized or petrified wood), olivine peridot (chrysolite), jadeite jade, tremolite-actinolite or nephrite jade, spodumene (kunzite, hiddenite), feldspar group (microcline amazonite, labradorite, orthoclase moonstone, oligoclase sunstone), turquoise, lapis-lazuli, and opal.

Wednesday, April 22, 2009


The most common cause of color in gemstones is the presence of a small amount of a transition metal ion. These transition metal ions have an incomplete set of 3d electrons. Changes in the energy of these electrons correspond to the energy of visible light. When white light passes through a colored gemstone or is reflected by it, some of the energy of the visible light is absorbed, causing 3d electrons in the transition metal ion to undergo an energy change. The light that is transmitted or reflected appears colored, because those colors corresponding to 3d-electron energy transitions have been absorbed. The table lists several common gemstones, their chemical compositions, colors, and the origins of these colors.

GemFormulaColorOrigin Of Color
RubyAl2O3RedCr3+ replacing Al3+ in octahedral sites
EmeraldBe3Al2(SiO3)6GreenCr3+ replacing Al3+ in octahedral site
AlexandriteAl2BeO4Red/GreenCr3+ replacing Al3+ in octahedral site
GarnetMg3Al2(SiO4)3RedFe2+ replacing Mg2+ in 8-coordinate site
PeridotMg2SiO4Yellow-greenFe2+ replacing Mg2+ in 6-coordinate site
TourmalineNa3Li3Al6(BO3)3(SiO3)6F4PinkMn2+ replacing Li+ and Al3+ in octahedral site
TurquoiseAl6(PO4)4(OH)8A4H2OBlue-greenCu2+ coordinated to 4 OHG and 2 H2O
SapphireAl2O3BlueIntervalence transition between Fe2+ and Ti4+ replacing Al3+ in adjacent octahedral sites
AquamarineBe3Al2(SiO3)6BlueIntervalence transition between Fe2+ and Fe3+ replacing Al3+ in adjacent octahedral sites
DiamondC Colorless pale blue or yellow Colorcenters from nitrogen atoms trapped in crystal

Tuesday, April 21, 2009

Featured Gemstones

People in every era and from all walks of life have adorned themselves with the dramatic, radiant grace of colored stone jewelry. The world of colored stones is vast and varied, and a true understanding of them requires knowledge of both science and history. Here are just a few of the most popular colored stones today.


Alexandrite is one variety of the mineral chrysoberyl, named after Czar Alexander II of Russia. It was discovered in 1831, in the Ural Mountains of Russia, and is composed of BeAl2O4.

Alexandrite is unusual because it is a grass green in daylight and raspberry red in artificial, incandescent lighting. The trace element chromium is responsible for both the red and green of alexandrite. This same trace element is responsible for the green of emerald and red of ruby when is substitutes for aluminum in the crystal structure. The coloring agents are dependent upon the wavelength of light and the crystal structure/chemical bonding; the chromium in alexandrite is such that the color changes with wavelengths of light, from natural sunlight or fluorescent lighting, where is appears green, to indoor incandescent light, where is appears red.

Alexandrite has a hardness of 8.5 on the Mohs hardness scale, and has excellent toughness. Alexandrites are typically transparent, and may contain fingerprint and silk inclusions.


Emerald is the deep green variety of beryl, an aluminum berylium silicate, Al2Be3(Si6O18). It is a cyclosilicate and often found in hexagonal primatic crystal forms. Beryl is 7.5-8 on the hardness scale and a vitreous luster. It has a conchoidal fracture and a brittle tenacity, which makes it sensitive to pressure and heat. Specific gravity is average to medium high, 2.66-2.87, and the refractive indices are 1.562-1.602. Although beryl may have an irregular distribution of color, the color is stable in light and heat. Asterism and cat's eye stones are possible. The best known variety of beryl is emerald, a deep green color. The green coloring agent is the impurity element, chromium, and possibly some vanadium. Some believe chromium defines emerald, whereas beryl colored with vanadium is merely green beryl. The finest emerald are transparent but more commonly they are clouded with inclusions. Dispersion is 0.014 and emerald has distinct pleochroim, showing blue-green and yellowish-green. It has no fluorescence but emerald shows bright red through the color or Chelsea filter.

Colombia is one of the largest commercial producers of emerald. Fine Colombian emeralds are highly regarded for their excellent color. Zambia is also a commercial source of emeralds with good clarity. Other sources include Afghanistan, Brazil, Pakistan, Russia, and Zimbabwe.


Opal is a hydrated silica, SiO2(H2O), that is lacking in crystal structure or is amorphous. The hardness is 5.5-6.5 and opal has a low specific gravity at 1.98-2.20. It has a conchoidal fracture and is brittle. Opal contains water, from 3-30%, and this over time will be lost, diminishing the opalescence (Schumann, 1997, p. 150). There are basically three types of opal: precious opal (containing flashes of fire), the orangish-red "fire opal" (named for its color, not flashes of fire), and common opal.

High heat or sudden temperature change can cause fracturing. Opals are generally stable to light, but heat from intense light can cause fracturing (known as "crazing"). Opals are attacked by hydrofluoric acid and caustic alkalis. Loss of moisture, and crazing, can result from storage in airtight containers, such as safe deposit boxes.

Pearl and Cultured Pearl

Pearls have been valued for their natural beauty, no faceting or polishing required, for some 6000 years. Approximately 70% are strung and worn as necklaces. Pearl quality is determined according to shape, color, size, and luster. Spherical are the most valued, but many pearls are irregular shapes, which are termed baroque or barrel pearls. Extreme dryness or moisture are both damaging conditions for pearls, as well as acids, perspiration, cosmetics, and hair spray. The low hardness means pearl is easily scratched and therefore storage is an important consideration.

High heat can burn cultured pearls, or cause discoloration, splitting or cracking. Pearls are generally stable to light but heat from intense light can cause dehydration and nacre cracking. Pearls are attacked by many chemicals and all acids. Hair spray, perfume, cosmetics, and even perspiration can damage nacre.


Peridot (pronounced pear-a-doe) is the gem variety of the mineral olivine, and also called chrysolite. It is a magnesium iron silicate, (Mg, Fe)2SiO4, with a hardness of 6.5-7, and specific gravity of 3.28-3.48. Cleavage is indistinct and the fracture, conchoidal. Crystal form is rare, although it is in the orthorhombic crystal system. It is doubly refractive with refractive indices of 1.63 and 1.695 ). Pleochroism is weak and peridot has no fluorescence.

Peridot stability is Rapid or uneven heat can cause fracturing in peridot. The gem is stable to light, but is attacked easily by sulfuric acid, and less easily by hydrochloric acid. Long-term exposure of perspiration may also attack peridot.


Ruby occurs in metamorphic rocks, dolomitic marble and gneiss, whereas sapphire may be found in sedimentary limestones, metamorphic marble, and igneous basalt, pegmatites, or andesite dikes. Corundum is very rarely mined from primary deposits, but typically mined from secondary alluvial or placer deposits, where this resistant mineral becomes the sand and gravel of stream beds. Ruby and sapphire have been synthesized since the end of the 19th century for industrial and gem quality uses. Synthetic star ruby and sapphire have been marketed since 1947.

Heat can cause a change in color or clarity, it can also damage or destroy fracture- and cavity-fillings. Rubies are generally stable to light, but bright lights can cause oil to leak or dry out. Chemicals can harm fillings and remove oil; soldering flux containing boron and firecoat made with boric acid powder, will etch the surface of even untreated stones.


Spinel is a good candidate for the title of “History’s Most Under-Appreciated Gem.” Some ancient mines that supplied gems for royal courts from Rome to China produced spinels, but they were usually confused with better-known stones like ruby and sapphire.

Spinel’s color range includes violet, blue, orange, red, pink, and purple. Blue spinels are often grayish and subdued, but the best are a deep rich color. The reds can rival fine ruby. And the vivid orange to orange-red stones merit their trade name—flame spinel. Some spinels show color-change, usually turning from grayish blue in daylight or fluorescent light to purple under incandes­cent light.


Tanzanite is a member of the zoisite group, as is thulite, the national gemstone of Norway. Thulite is an opaque, pink gemstone usually cut en cabochon, and is named after Thule, an old name for Norway. The gem quality transparent zoisite, tanzanite, varies from a deep "sapphire" blue to an "amethyst" purple. It is now one of the birthstones accepted for December birthdays and is a calcium aluminum silicate, Ca2Al3(O/OH/SiO4/Si2O7).

Tanzanite is special-care gem for two reasons: sensitivity to thermal shock and the potential for cleavage. Sometimes the temperature change between the hot lights of the display case and the chilly glass countertop in an air-conditioned showroom can be enough to develop cleavages in tanzanite.


Topaz is a nesosilicate, Al2[(F,OH)2/SiO4], and 8 on the hardness scale. It is in the orthorhombic crystal system, which is reflected in the commonly found prismatic crystal form with orthorhombic pyramid terminations. It has perfect basal cleavage, as well as a conchoidal and uneven fracture. Topaz is transparent and translucent, with a vitreous luster, and high specific gravity, 3.49-3.57. It is doubly refractive, 1.609-1.643, with a strong to definite pleochroism (with the exception of blue topaz, which as weak to none), and weak fluorescence. When topaz is gently heated or rubbed, it becomes electrically charged. Topaz occurs in cavities within granite or rhyolite igneous rock, pegmatite dikes, high temperature quartz veins, and/or alluvial deposits.

The largest faceted gemstone ever recorded is the "Champagne Topaz." The gem was mined in Brazil, weighs 36,854 cts. and measures 34.9 cm x 15.5 cm x 12.1 cm.


Turquoise is hydrous copper aluminum phosphate, CuAl6[(OH)2/PO4]4 4H2O (Schumann, 1997, p. 170). It varies in color from a sky blue to blue-green or apple-green, and is frequently fashioned with the matrix rock and interspersed vein rock. The veined material is called "spiderweb" turquoise. The blue color changes to green with high heat (of soldering) and exposure to light, perspiration, oils, cosmetics, household detergents (always remove turquoise rings before washing hands or dishes). It has a hardness of 5-6, cleavage, and a conchoidal fracture. The specific gravity is 2.31-2.84 and it is in the triclinic crystal system, crystals are rare. It has a waxy luster and both the fluorescence and pleochroism is weak.

Historically, the finest material was mined in Iran and is known as Persian turquoise. This source is no longer commercially important. Today, the United States is the major source of turquoise. Other sources are China, Chile, Australia, and Mexico.

Common Measures For Gemstones

Diamonds are valued primarily as gemstones. Uncut diamond prices climbed nearly 50 percent between 2002 and 2006 due to growing world-wide markets. Prices of rough diamonds from active mines around the world recently averaged from as little as US$20 per carat to more than US$100 per carat ($2,835 to $14,175 per ounce).

Monday, April 20, 2009

Where were diamonds first Occured?

Diamonds occur in two general types of deposits world wide:

  • volcanic pipes, also known as kimberlite pipes
  • alluvial, or placer, deposits, which were formed by the erosion of diamond pipes over millions of years.

The following is not required information for students of EPS 2

The earliest productive mines were in the Golconda region of India, particularly along the Kristna River. After 1725 this mining district was gradually eclipsed in importance by the diamond deposits of Brazil. Diamonds were first mined there along the Jequitinhonha River, in the Diamantina area of the state of Minas Gerais.

In 1867 a 21-carat stone was discovered on the banks of the Orange River near Hopetown, South Africa. A great diamond rush started, and new deposits were discovered that were more productive than any the world had ever known. Another major diamond resource was developed in the 1950s in the Yakutia region of the Soviet Union. By the 1980s the Yakutia and South African regions and the country of Zaire dominated the world's diamond market. The mineral has also been found in smaller amounts in numerous other places. In the United States the leading producers include Arizona, Nevada, and Montana, although the largest gemstones have been found in an eroded volcanic pipe in Pike County, Ark.

For many years, microscopic diamonds have occasionally been noted in meteorites; they were attributed to high-speed collisions in space or with the Earth. In 1987, however, following the discovery of many more such diamonds, the theory was developed that they are the product of ancient supernova explosions of giant stars.

In recent years, diamonds have been found in unusual metamorphic rocks that were subjected to very high temperatures and pressures.

Sunday, April 19, 2009

1,200 Carats of Possible 'Blood Diamonds' Seized at JFK

Jamaica, N.Y. - On Saturday, Customs and Border Protection officers at JFK International Airport seized almost 1,200 carats in diamonds. The 28 rough diamonds originated from Sierra Leone and were seized because they did not have Kimberley Certificates which are required by the Clean Diamond Trade Act.

The diamonds were destined for Brentwood, N.Y. and had a declared value of more then $800,000.

Two U.S. jewelers, arriving from Sierra Leone via London, declared that they were transporting rough diamonds and 57 pounds of gold dust. The two U.S. citizens, whose names are being withheld for privacy reasons, were referred for a baggage exam to verify proper documentation for entry. Unset stones are generally duty free when imported from most countries; however, a formal entry must be filed on all rough diamonds and all required documents must be available for inspection.

Saturday, April 18, 2009

Where Diamonds Are Found?

Diamonds are found on continents and are associated with past volcanic activity. Cratons, which are the oldest parts of a continent, are especially favorable for hosting diamonds because they are older than the newer crust. As the older crust contained volcanoes, kimberlite and lamproite magmas transported the diamonds to the surface. When these old volcanic magmas called kimberlite pipes are uncovered, they are susceptible to weathering, leaving the diamonds exposed on the surface of the Earth.

Recent Research on the Napoléon Diamond Necklace

The Napoléon Diamond Necklace.

Original box of the Napoléon Diamond Necklace, made in Paris.

Details of the Napoléon Diamond Necklace.

Disc-shaped tension halos, probably around sulfide crystals, as inclusions in one of the diamond.

Microscope coupled with an infrared spectrometer used to acquire infrared spectra of diamonds in the Napoleon Necklace.

The Napoléon Diamond Necklace under ultraviolet light. The diamonds are labeled as to their type. Most diamonds exhibit a blue fluorescence with various intensities; several diamonds have a pinkish orange luminescence; the rest are non fluorescent.

Friday, April 17, 2009

Types of Diamonds

Grey Diamonds

Black Diamonds

Carbonado, commonly known as the 'Black Diamond,' is a natural polycrystalline diamond found in alluvial deposits in the Central African Republic and Brazil. Its natural colour is black or dark grey, and it is more porous than other diamonds.

Purple Diamonds

Red Diamonds

Violet Diamonds

Chameleon Diamonds

Green Diamonds

Blue Diamonds

Yellow Diamonds

Champagne Diamonds

White Diamonds

Pink Diamonds

History of Diamonds

Diamonds are the hardest substance known on Earth. They make sparkling jewelry as well as saw blades that can cut through pretty much anything. Diamonds form deep within the Earth's mantle layer from the element carbon that is under huge amounts of pressure from the load of rocks above.

Recently, scientists studying diamonds have found the ages of thousands of diamonds from Southern Africa, where most diamonds are found. They discovered that there were only three times during Earth’s history when diamonds were made and that Earth no longer makes diamonds like it used to. “Something was different then. Perhaps the planet was hotter on the inside, or the composition of the rocks was subtly different. Whatever it was it has changed now,” stated Steve Shirey, one of the project scientists.

The oldest diamonds were made 3.3 billion years ago when Earth was rather young. The second time diamonds were made was 2.9 billion years ago. The scientists think that these diamonds were probably formed from rocks that lay at the bottom of a shallow sea. The carbon that made these diamonds probably came from ancient sea life. The youngest diamonds on Earth are 1.2 billion years old although a few smaller diamonds are about 100 million years old.

Some people like diamonds because they are pretty, rare, or expensive but Dr. Steve Shirey has a different view. “I think of diamonds,” he said, “as being tiny time capsules that encase a little piece of rock protecting it for billions of years and providing us with a unique window on ancient times.”

Thursday, April 16, 2009

Diamond Research

New research in South Africa shows possible explanation for how Bushveld platinum ores were created

Did You Know?-The Northwest Territories is One of the World’s Largest Producers of Diamonds

  • The diamond is the official gem of the Northwest Territories.

  • The discovery of diamonds in 1991, at Lac De Gras resulted in the largest staking rush in Canadian history.

  • BHP’s Ekati mine in the NWT was Canada’s first diamond mine. Construction began in 1997 and it opened officially on October 14, 1998.

  • Since 1998, about 78,947,507 carats worth of gem quality diamonds have been mined in the NWT – with an estimated value of $11.368 billion/CAD.

  • De Beers’ Snap Lake Mine is Canada’s first fully underground diamond operation – and the first mine ever built by the world’s diamond giant outside of Africa.

  • The collective operations of the Ekati, Diavik and Snap Lake diamond mines are producing 15% of the world’s rough diamonds. Diamond production for 2007 reached 16.6 million carats worth $1.4 billion.

  • Canada is the third largest diamond producer by value in the world after Botswana and Russia.

  • Since 1996, the NWT’s diamond mines have provided over 16,000 person years of employment – over 4,400 to Aboriginal residents and have surpassed $5 billion in investment with northern and Aboriginal businesses.