The definition of a gemstone is broad: the term can be used to describe any mineral that is highly prized for its beauty, durability, and rarity. A gem is a mineral enhanced in some manner by altering its shape, usually by cutting and polishing.
Most gems begin as crystals of minerals (such as diamonds or sapphires), or as aggregates of crystals (such as malachite or jadeite). A limited number of noncrystalline materials of organic origin (such as pearl and amber) are also classified as gemstones, and are usually referred to as organic gems.
THE BEAUTY OF GEMS
The prime requisite for a gem is that it must be beautiful.
A gemstone can owe its beauty to various properties: its depth of colour or transparency; its colour pattern, as seen in opal or agate; the intensity of its brilliance; or the pattern light makes within it, as seen in star sapphires or cat’s-eye chrysoberyl. It must also remain beautiful, withstanding wear and preserving its polish or other finish.
A number of otherwise beautiful gemstones are too soft or too brittle to wear, and are cut only for collectors. More than 4,000 minerals have been identified, but fewer than 100 are used as gemstones.
Of these, only a minority are of major importance: diamond, corundum (sapphire and ruby), beryl (green emerald and aquamarine stone), chrysoberyl, feldspars (sunstone, moonstone, and labradorite), garnets, jadeite and nephrite (jade), lazurite (lapis lazuli), olivines (peridot), opal, aragonite (pearl), quartz (in all its varieties), spinel, topaz, tourmalines, turquoise, and zircon.
Gems are usually divided into two categories: precious and semiprecious. Diamond and the two color varieties of corundum, sapphire and ruby, are considered precious, as is the deep green variety of beryl, emerald.
EARLY USES OF GEMS
The use of gemstones goes far back in human history: people were adorning themselves with shells, pieces of bone, teeth, and pebbles by at least the Upper Paleolithic period (25,000-12,000BC). Bright colours or beautiful patterns drew people initially, and when the shaping of stones for adornment began, the stones chosen were opaque and soft.
As the techniques of shaping improved in essence, the first gem cutting – other, harder stones were employed Carnelian and rock crystal beads, both varieties of quartz, which is relatively hard, were fashioned at Jarmo in Mesopotamia (now Iraq) in the 7th millennium BC.
The next technical leap in cutting also took place in Mesopotamia, with the engraving of cylinder seals: finger-sized, engraved stone cylinders used as a means of identifying goods. When the seal was rolled on damp clay, a unique imprint resulted. The cylinder seals were also valued as adornment and possibly a symbol of status.
Records of the time are the first indicating the belief that stones themselves have a “mystic” value – beliefs that persist today in the wearing of birthstones, and in New Age uses. The Egyptians, Babylonians, and Assyrians all believed that coloured stones had he properties.
The choice of stones and other healing materials was dictatet by the colours that the disease under treatment caused in the body: yellow jaundice, blue lips, or fever-red skin, for example. Other coloured materials, such as plants, were considered equally effective, but stones retained their colours over time.
NEW AGE BELIEFS ABOUT CRYSTALS
Gemstones have been associated with particular months of the year since ancient times.
In astrology, each of the 12 signs of the zodiac is associated with one or two gemstones, which are thought to resonate with the essential character of the person born under that sign, and consequently to bring the person luck. A hugely contentious subject between scientists and New Age practitioners is that of “crystal healing”.
Crystal healers claim that certain crystals – particularly quartz – give off “healing energy” when placed on the body, a claim contested by mineralogists, who recognize the impossibility of this given the minutely bound and intricately balanced energies that create a crystal in the first place. Yet anecdotal evidence from many sources suggests that when patients are treated by crystal healers, healing does occur in many instances.
A new field of medical research suggests that the state of the immune system (and hence the state of health) is profoundly influenced by both conscious and unconscious mental and emotional factors. Perhaps it is the belief that the crystal will heal the body that causes it to heal, rather than the crystal itself.