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Gemstone Basics

gemstone anatomy

Gemstones are mere shards of common earthly elements, yet those elements are so exquisitely combined they have elicited the best and worst in human emotion for centuries. Gems have inspired love, hate, envy, greed, poetry and lust. The beauty of a fine gem is beyond description and that is much of what makes it a gem

Gems are durable. Diamond is king of hardness at 10 on the mohs scale. Gems with a Mohs hardness of 8 and above will be highly resistant to abrasion over time.

Fine gems are rare. They come from the earth, mostly as a result of volcanic activity, growing and forming into crystal structures. But only a tiny fraction of these combinations of elements display the appropriate color, transparency and size to be gems.

Then they hide from us beneath tons of rocks in inaccessible regions spanning the universe.

If a crystal does not pass the test of beautiful, durable and rare, then it cannot be a "Gem".

Gem Terms Commonly Used with Faceted Gems

  • Carat - Measure of weight; 1 carat = 1/5 gram
  • Color - Referred to technically as Hue
  • Proportions - dimensions and geometric ratios used in fashioning gems
  • Clarity - the absence or presence of internal characteristics.

Gem Carat Weight Related to Value

A carat is 1/5 of a gram and commonly divided into points. 1 carat = 100 points. It is common to hear small gemstones called "X pointers".

Gems are normally priced per carat. Do not assume a price is for the gem unless it is specifically stated.

The larger the gemstone, all factors being equal, the higher its price per carat. Most gems have value thresholds. (ex) A .51 carat ruby is worth more per carat than a gem of identical quality of .49. Other thresholds are 1 carat, 2 carat and 5 carat.

For a more detailed presentation on a greater variety of gems, visit The University of Texas Gemology Program Site. It is excellent and goes far beyond the scope of the Asia-Gems.com site.

You can study crystallography online at Crystallography and Mineral Crystal Systems  an exceptional site by Mike and Darcy Howard who do a much better job of discussing crystals than we ever could.