Gems are minerals by composition but not all minerals are considered gems. In many instances the definition of which minerals are gems is an arbitrary one, influenced by fashion. There are three major criteria for classification of a mineral as a gem—beauty, durability and rarity.

Beauty is a purely subjective quality, determined by fashion and tradition. One of the characteristics of beauty used in the description of many gems is luster another is color. Luster is the ability to reflect light. It is luster that contributes to the “precious” quality of transparent gems. On the other hand, it is the richness of color that determines the beauty of the opaque or “semi-precious” gems.

Durability is that quality that entails both hardness and toughness. A gemstone has to be sufficiently tough as well as hard for it to be used in jewels such as rings which are subject to rough wear. Hardness is that quality that indicates a mineral’s resistance to scratching or piercing. Toughness defines a mineral's ability to resist breakage.

Most gemstones are rare. In fact, “gem quality mineral” make up 1% of the earth’s substance. However, the perceived rarity of certain gemstones stems mostly from the dictates of great marketing. Diamonds are rare. Marketing of diamonds has made this gem seem rarer than it actually is in nature. Remember that most women own at least one diamond. There are rarer gems but they do not command the same price as diamonds, because, marketing is not on their favor.

One of the more rare gems out there is Larimar. Larimar is only found in small quantities in a specific area, the Dominican Republic. Another rare gem is Iolite. Found only in a few places on earth. Other gemstones that are rare are Gaspeite and Sugilite. Gaspeite is a green stone raging in color from light green (almost apple green color) to bright neon green. Gaspeite is found only in a couple of places. Gaspeite comes from the Gaspe Peninsula, Quebec, Canada where it was originally found and from Western Australia. There are three well known Sugilite mines. However, accessibility to these mines is several hundred feet under ground. This makes the mining for Sugilite very difficult and expensive. These are only a few examples of some rare gemstones. There are many more out there and still many more, yet, to be discovered.



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