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GEMS May – Mines and Types of Emerald

by JewelStruck on May.20, 2010, under GEMS

Moving ahead with second post on Gemstone Each Month Series (GEMS) for May, we would be discussing about Mines and Types of Emerald. Also showcasing a very beuatiful Indian Emerald Necklace at Natural History Museum – Washington DC. If you would like to share anything on Emeralds, do email us at

Washington DC - Natural History Museum - Indian Emerald Necklace

Emeralds are generally classified by the place they come from, so we would discuss about the types and mines of Emerald together.

  • Zambian Emerald – although discovered in the late 40’s was not commercially mined until the 1950’s. Zambia, today is one of the worlds’s leading producers of fine Emerald. Its known for its intense color, remarkable clarity and retains its magnificent hue even in small stones of less than 0.5 ct. This makes it most highly prized variety of Emerald.
  • Columbian Emerald – Columbia is the biggest producer of emeralds these days, both in terms of quantity and quality. These are mainly sought after for the large crystals and therefore bigger stones.
  • Sandwana Emerald – Coming from Zimbabwe, they have stunning color and are known for the inclusions inside. They look very similar to Zambian Emerald.
  • Brazilian Emerald – Brazil has been supplying emerald to the world market since the 1980s. Brazilian emeralds are generally lighter and yellowish in shade.

Emeralds are found in many other countries too – including Afghanistan, Australia, Austria, Brazil, Bulgaria, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania and United States.

Syenthetic Emerald – The first commercially successful emerald synthesis process was that of Carroll Chatham. However the process did not run out to be commercially much viable. Another process known as hydrothermal flux process by Pierre Gilson Sr., began to be used in the production of synthetic emerald since 1964.

So this was all we had for mines and types of Emerald, we will be back with more info on Emeralds sooner. If you want to share anything, do email us.

Image Credit :- thisisbossi

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GEMS April – Types of Diamond

by JewelStruck on Apr.21, 2010, under GEMS

Continuing with Gemstone Each Month Series (GEMS) for April month, we would be posting about types of Diamonds. Also showcasing a very beautiful Diamond ring by rcnevada. If you have anything to share on Diamonds, do email us as

Diamond ring by rcnevada

Coming back to types, Natural Diamonds can be categorized into 4 types, depending on the impurity levels.

  • 1a – It is the most common form of Diamonds and contains about 0.3% of Nitrogen. It absorbs blue light and so are generally light yellow or brown in color.
  • 1b – They are very rare in nature, about 0.1% of total. In them the nitrogen atoms occur isolated throughout the carbon lattice. In general have a more intense color than Type Ia diamonds, absorbing green as well as blue light. They can appear yellow, orange, green or brown in color.
  • 2a – They contain very negligible amount of impurities and are considered purest form of Diamonds. These are generaly colorless.
  • 2b – They occour very rare and may contain even lower concentrations of nitrogen than 2a. But they contain boron impurities at the atomic level, because of which they are generaly bluish in color. They constitute about 0.1 percent of total

Other than natural Diamonds, diamonds can be synthesized too. Two of the methods used are High Pressure High Temperature Synthesis using graphite and another growth technique called Chemical Vapour Deposition(CVD).

So thats all we had on types of Diamonds, we will be back with next post in this series soon.

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GEMS January – Mines and Types of Garnet

by JewelStruck on Jan.20, 2010, under GEMS

Here we are, with another post in Gemstone Each Month Series (GEMS) on Garnets, for the month of January. We did some research on the mines and types of garnet, would be discussing the same in this post.

Garnets are usually mistaken as a single gem, but it is actually a family of gems. They are found all over the world including Latin America, Africa, India, Australia, Asia and some parts of Europe. The most common color of garnets is reddish brown whereas the most prized garnet is an emerald green variety called demantoid and is a member of the adradite group. Garnets are many a times found in the streams where metamorphic rock has eroded and left crystals for collection.

Pendant in uvarovite, a rare bright-green garnet

Types of Garnet used as gems are –

  • Pyrope – (from the Greek pyrōpós meaning “fire-eyed”) is red in color and chemically a magnesium aluminium silicate, though the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to almost black. Transparent pyropes are used as gemstones. A variety of pyrope from Macon County, North Carolina is a violet-red shade and has been called rhodolite, from the Greek meaning “a rose.” In chemical composition it may be considered as essentially an isomorphous mixture of pyrope and almandine, in the proportion of two parts pyrope to one part almandine. Pyrope is an indicator mineral for high-pressure rocks.
  • Almandine –  sometimes incorrectly called almandite, is the modern gem known as carbuncle. The name Almandine is a corruption of Alabanda, a region in Asia Minor where these stones were cut in ancient times. Chemically, almandine is an iron-aluminium garnet, the deep red transparent stones are often called precious garnet and are used as gemstones (being the most common of the gem garnets).
  • Spessartine Spessartine or spessartite is manganese aluminium garnet. Its name is derived from Spessart in Bavaria. It occurs most often in granite pegmatite and allied rock types and in certain low grade metamorphic phyllites. Spessartine of an orange-yellow is found in Madagascar. Violet-red spessartines are found in rhyolites in Colorado and Maine.
  • Grossular – Grossular is a calcium-aluminium garnet, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. One of the most sought after varieties of gem garnet is the fine green grossular garnet from Kenya and Tanzania called tsavorite. This garnet was discovered in the 1960s in the Tsavo area of Kenya, from which the gem takes its name.
  • Andradite – is a calcium-iron garnet, is of variable composition and may be red, yellow, brown, green or black. The recognized varieties are topazolite (yellow or green), demantoid (green) and melanite (black). Andradite is found both in deep-seated igneous rocks like syenite as well as serpentines, schists, and crystalline limestone. Demantoid has been called the “emerald of the Urals” from its occurrence there, and is one of the most prized of garnet varieties. Topazolite is a golden yellow variety and melanite is a black variety
  • Uvarovite – Uvarovite is a calcium chromium garnet. This is a rather rare garnet, bright green in color, usually found as small crystals associated with chromite in peridotite, serpentinite, and kimberlites. It is found in crystalline marbles and schists in the Ural mountains of Russia and Outokumpu, Finland. Uvarovite crystals are generally too small to facet and are left attached to a matrix and incorporated into jewelry.

So those were the six major types of Garnets. Hope you got enjoyed reading this post, if you would like to contribute or share anything on Garnets do email us at

References – Wiki

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GEMS December – Ruby Deposits and Types of Ruby

by JewelStruck on Dec.17, 2009, under GEMS

Continuing with Gemstone Each Month Series (GEMS) for December, we would be discussing about types of Ruby and places where ruby is mined. Just to remind you, we keep on including pics of Jewelry made using Ruby in each of our posts. So if you would like your Jewelry to be featured do mail us at Anyways, lets start with the places where ruby is mined.

Ruby Deposits

The Mogok Valley in Upper Myanmar (Burma) has produced some of the finest rubies ever mined. That region was for centuries the world’s main source for rubies. But very few good rubies have been found there in recent years. Blood red ruby with a hint of blue is sometimes described as “pigeon’s blood”.

The area of Mong Hsu (in central Myanmar) began producing rubies during the 1990s and rapidly became the world’s main ruby mining area.  Namya (Namyazeik) located in the northern state of Kachin is the most recently found ruby deposit in Myanmar.

Myanmar Ruby Rough

Historically rubies have been mined in Thailand, the Pailin and Samlout District of Cambodia, and in Afghanistan. They have been rarely found in Sri Lanka, where pink sapphires are more common.

Ruby deposits were found in Tanzania, Madagascar, Vietnam, Nepal, Tajikistan, and Pakistan after the Second World War.

In the U.S.  states of Montana, North Carolina, and South Carolina have some Ruby deposits. More recently, large ruby deposits have been found under the receding ice shelf of Greenland. In 2002 rubies were found in the Waseges River area of Kenya.

Ruby rough and polished state

Synthetic Rubies

Rubies were first synthesized in 1902. Frimy and Auguste Verneuil manufactured artificial ruby by fusing BaF2 and Al2O3 with a little Chromium at red heat. The process of creating synthetic rubies by flame fusion is known as the Verneuil process.  Many rubies on the market are synthetic. Only experts can distinguish between natural and synthetic rubies.

African Ruby Rough

Types of Ruby

  • Burmese or Burma Ruby – Ruby with exceptional color (generally but not necessarily from Burma)
  • Pigeon’s Blood Ruby – Blood-red ruby with a hint of blue
  • Star Ruby – Ruby displaying asterism – A star like effect caused by inclusions.
  • Cat’s Eye Ruby – Ruby exhibiting cat’s eye effect, i.e. concentrated narrow band of reflected light across the center.
  • Thai or siam Ruby – These come in darker shades and are only next to burmese ruby in quality.
  • Srilankan Ruby – These are lighter shades, mostly pink in color.
  • Madagascar RubyThe most recent discoveries of rubies have occurred in Madagascar at Andilamena and Vatomandry. The deposit in Vatomandry produces crystals of nice natural orange/red and pinkish color which do not require heating. The rough from Andilamena is more substantial and is generally somewhat violet and not very clean, but heat treatment improves the color substantially.
  • Vietnamese Ruby – Coming from mines in Vietnam – Luc Yen, north of Hanoi, and Quy Chau, to the south. Its as good as Burmese ruby and still unexploited.
  • Tanzanian or Longido RubyTanzanian rubies from the Songea deposit are darker and more garnet like in color than Burmese rubies and as a result are also much more affordable
  • Verneuil Ruby – Synthetic Ruby, made using Verneuil process described above.

Image credits : topofthailandgems, diamondvues

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