Thursday, 25 October 2012

I Do Love Gemstones

This is really no secret, that I love my gemstones, you probably do as well.  So, sometimes, it's also nice to know a few tidbits of information about the stones we love. There are charming legends attached to gemstones.  I just love the way they look.   Here are but a few of my favorites:

A Dutch colonel, H. Von Prehn, is credited with discovering Prehnite in 1774 at the Cape of Good Hope in Africa. Early traders nicknamed the gemstone Cape Emerald in hopes of exploiting its green color.  Prehnite was originally classified as a Zeolite, due to the fact that it usually forms in the same areas and under similar conditions as the zeolite.   Today geologists place it in the phyllosilicate category which also includes apophylite.  Prehnite is a fairly strong crystal, quite resistant to pressures and scratching. It is composed of aluminum, calcium and silicon with a few specimens containing small trace of iron as well. It is considered a secondary or second stage mineral, meaning that the crystal did not form during the initial volcanic activity, but instead the crystals were form by events caused by the volcano, much after the fact.  Initially Prehnite was rare, South Africa being the only known location for many, many years. Eventually pockets of the stone were found throughout the world, including the US, Canada, Austria, Germany, France and India.

Amazonite is semi-opaque stone that was used extensively by the Egyptians it is called the stone of courage and is said to have received its name for the Amazon women warriors who worshiped the moon goddess Diana. Some say it's name was given due to the fact that it was discovered near the Amazon River.  Amazonite is a type of feldspar with crystallines in the form of short prismatic crystals, tabular crystals or mass. it usually occurs in the turquoise color and is sometimes found with yellow, white or grey portions.


Fluorite belongs to the spar family, as all other family members, fluorite can be separated into flakes. According to folklore, it is the home of the rainbows.   Formerly called fluorospar, fluorite has limited use as a gemstone due to its relatively soft demeanor, However, the wide range of colors and the frequent incidence of more than one color in a singe specimen has made this an interesting stone and a wonderful display of colors when used as beads or other jewelry components.

Labradorite is the plagioclase feldspar.   Labradorite has also been found in some meteorites.  Gem quality labradorite is known as spectrolite; which is a colorless variety, darkened with needlelike inclusions, often called black moonstone.  Spectrolite is a dark and opalescent blue with a shimmer when the light hits it. It was discovered in Finland during WWII, and it is also called falcon's-eye.  According to an Eskimo legend, the Northern Lights were once imprisoned in the rocks along the coast of Labrador. It is told that a wandering Eskimo warrior found them and was able to free most of the lights with a mighty blow of his spear. Some of the lights were still trapped within the stone, and thus we have today the beautiful mineral known as labradorite.  Labradorite which shows an iridescent play of colors is used in jewelry and lapidary items, and as an ornamental stone it has many popular uses such as in decorative clock faces, table and counter tops, facing for buildings, etc.  Traditionally, Labradorite is thought to bring good luck.

At one time, Peridot was more valuable than diamonds. This gemstone is actually known by three names: Peridot, Chrysolith and Olivin, because peridot is the gemstone variety of the olivin mineral. In the gemstone trade it is generally called peridot, a name derived from the Greek word "peridona", with a meaning along the lines of "giving plenty".
Peridot is one of the few gemstones which exist only in one color. Finest traces of iron account for the deep green color with a slight golden hue. Chemically Peridot is just an iron-magnesium-silicate, and the intensity of color depends on the amount of iron contained. The color as such can come in any variation from yellow-green and olive to brownish green. Peridot is not especially hard – it only achieves about 6.5 to 7 on the Mohs´ scale – and yet it is easy to care for and quite robust.  The most beautiful stones come from the Pakistan-Afghanistan border region. Peridot as gemstone does also exist in Myanmar, China, the USA, Africa and Australia. Stones from East Burma, today’s Myanmar, show a vivid green with fine silky inclusions. Peridot from the American state of Arizona, where it is quite popular in Native Indian jewelry, often shows a yellowish to golden brown shade.


Garnets are a related group of minerals. Members of this group include: almandine (dark red to violet red); spessartite/spessartine (orange to reddish-brown); Pyrope (blood red); Grossular (white, yellow, yellow-green, brownish-red, orange or black); andradite (colorless to black). The most prized garnet is an emerald green variety called Demantoid and is a member of the andradite group.  The name "garnet" comes from the Latin granatus, a grain possibly in reference to malum garanatum (pomegranate) a plant with red seeds similar in shape, size and color to some garnet crystals.  There is a common misconception that all garnets are a red gem, they do, in fact, come in a wide variety of colors including purple, red, orange, yellow, green, brown, black, or colorless. 
The lack of a blue garnet was remedied in 1998 following the discovery of color-change blue to red/pink material in Bekily, Madagascar.   These stones are very rare.  Color-change garnets are by far the rarest garnets (except Uvarovite, which does not come in cuttable sizes). In daylight, their color can be shades of green, beige, brown, gray and rarely blue, to a reddish or purplish/pink color in incandescent light. By composition, these garnets are a mix of Spessartine and Pyrope, as are Malaya garnets. 






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