Gemology & Mineralogy
Labradorite
NaAlSi3O8 or CaAl2Si2O8
Labradorite is a member of the family of feldspar crystals which can range in color from colorless to yellow to grey. Either yellow or grey labradorite may reflect light as iridescent flashes of blue, green, red, or gold. The cause of what is known as "labradorescence" is the inclusion of Schiller, and the effect of its iridescence is second only of the rainbow moonstone. Other feldspar such as the sun-stone and andesine crystal are grouped with labradorite feldspar. Andesine is believed to be the result of diffuse copper or lead inside the yellow labradorite crystal. While zircon or magnetite may also be found in a specimen, labradorite found in nature should be treated as a crystal matrix material.
Tektites
Tektites are molten silicates formed after a meteor impact. One example being Moldavite, a bottle-green gem first discovered in 1787 at the Moldau River. The popular idea about tektites are that they cooled as molten glass in the are so are found at the impact site. Another idea about tektites due to high temperatures as meteors are moving through the atmosphere says tektites are of extraterrestrial origin.
Opal
SiO2•nH2O
Opals are a wonderful gem because the individual opal has all the colors of the rainbow. The inclusions are described as flashes, sparks, or flames of light, playing along the surface of the opal. The finest variety of opal, called the Harlequin Opal, has multicolored flakes throughout the gemstone; while, the Mexican Opal are more transparent with patches of coloring. However, the Fire Opal also comes from Mexico which has but one color: a fire-like red. Unfortunately, the range of "fire-like" red ranges into yellow. Opals are mined soft and brittle then harden due to exposure; eventhough the most hardened opal may still chip, many of them are cut for settings.
Chrome Diopside
The Russian Emerald
Diopside is mined at Yakutia, Siberia, and only recently been available on the commercial market. Since mining is limited to non winter months, its availability is limited — as much so as 99% of Russian diamonds. The export of chrome diopside is only due to the liberalization of the Soviet economy, thus, the gemstone becomes rather limited to smaller sizes. As the formula indicates, chromium is a trace element inside the diopside, CaMgSi2O6, lattice. Chrome diopside is colored by the same element that gives emerald its color. For this reason, the diopside is often called “Russian emerald”. The affordable price of chrome diopside at its debut in 1988 made it popular compared to other green gemstones such as chrome tourmaline and the tsavorite garnet. Typically, chrome diopside is found under three carats for larger specimens appear to be almost black.
Garnets
X3Y2(SiO4)3
The chemical formula for garnet is multivariate consisting of two parts Y-component and three parts X. A consequence of this chemistry is all the different types of garnets which are listed as the following: pyrope, almandine, spessartine, grossular hessonite, grossular tsavorite, uvarorite, and andradite. As late as the 14th century, the word “garnet” in Middle English meant “dark red”, so more or less described the color much in the same way topaz did for the color yellow. Although, France’s word for “grain, seed” was similarly worded as “grenate”, the sign for a garnet may possibly be related to the pomum granatum, the humble pomegranate — that connection of the seed to a mineral is reserved for the red zircon.
Although the reddish garnet is the most frequent, they come in all of the colors including colorless. The opaque varieties however are used as abrasives; for the rest, it’s their transparency which makes them an ideal gemstone. Garnets are hence categorized as semi-precious.
The Crystal Cosmos
Quartz crystal can be both beautiful and useful. Overall, we encourage our customers to buy crystal for its beauty, however, we also consider its metaphysics. To that end, we offer books and advice that is intended to enhance the experience with and enjoyment of gemstones.
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