Posts Tagged gems by james

Gems by James: August Birthstone is Peridot

Posted by on August 4, 2010 at 16:43 pm

The birthstone for August is Peridot.

A transparent yellowish-green Magnesium/Iron Silicate, Peridot is a gem variety of the mineral Chrysolite or Olivine. Peridot ranges in color from light yellow-green, olive green and brownish green. The intensity and tint of the green depends on the crystal’s iron content. The most valuable gem is the dark-olive green color. Tinges of brown or visible flaws greatly diminish the gems value.

August Gemstone PeridotOlivine, of which peridot is a type, is a common mineral in mafic and ultramafic rocks, and it is often found in lavas and in peridotite xenoliths of the mantle, which lavas carry to the surface; but gem quality peridot only occurs in a fraction of these settings. In general, Olivine is a very abundant mineral but gem quality peridot is rather rare.

In the U.S., Peridot olivine is mined in North Carolina, Arizona on the San Carlos Reservation, Hawaii, Nevada, and New Mexico. And, it is also mined in Australia, Brazil, China, Kenya, Mexico, Myanmar (Burma), Norway, Pakistan, Saudi Arabia, South Africa, Sri Lanka, and Tanzania.

NOTE: Peridot can be special ordered from Gems by James. Please contact us for additional details.

Gems by James: May Birthstone Emeralds

Posted by on April 30, 2010 at 17:55 pm

The traditional birthstone for the month of May is Emerald, which is the green variety of the mineral Beryl.

Many consider the beautiful green color of emerald to be unparalleled in the gemstone world. The presence of trace amounts of chromium and sometimes vanadium give the gemstone it’s color. Unlike many other beryls, emeralds commonly contain inclusions and other natural flaws making them susceptible to breakage.

May Birthstone Emerald - Gems by JamesThe Egyptians mined emeralds in Austria. And, a rare type of emerald known as a “trapiche emerald” is occasionally found in the mines of Colombia. A trapiche emerald exhibits a “star” pattern and it has ray-like spokes of dark carbon impurities, which creates the six-pointed radial pattern.

The main source of emeralds are three mines in Colombia: Muzo, Coscuez, and Chivor. Emeralds are also found in many other countries, such as 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, United States, Zambia and Zimbabwe.

In the United States, emeralds have been found in Connecticut, Montana, Nevada, North Carolina and South Carolina as well as the Yukon (discovered in 1998).

Gems by James cuts emeralds to order. They are special stones and deserve a craftsman’s hand. Contact us if you would like to discuss a very special emerald gift for Mother’s Day or a birthday.

At 858 carats (172 g), the Gachala Emerald is one of the largest emeralds in the world. It was found in 1967 at La Vega de San Juan mine in Gachalá, Colombia. It is at the National Museum of Natural History of the Smithsonian Institution in Washington, D.C.

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