Gemstones also called gems or jewels are rare minerals and few noncrystalline materials of organic origin (e.g., pearl, red coral, and amber).
They are the result of crystallization under high pressure. The vivid colors and attributes of gemstones owe it to the presence of impurities during the stage of crystallization. Moreover, these impurities become inclusions, giving rise to optical phenomena in the gemstone.
Of the more than 2,000 identified natural minerals over 130 species have been cut into gems.
Gemstones have attracted humankind since ancient times, and have long been used for jewelry.
Archaeological evidence shows alluvial gemstones and mining in ancient Egypt. In addition, history says, Sinai Malachite was lucrative to miners in 6th Millennium BCE owing its value. Moreover, Pliny’s Natural History records show Emeralds from Coptos hills.
The Ancient Greeks began to decide which gems are precious and semi-precious. This continued in other cultures. In modern times, the precious stones are diamond, ruby, sapphire, emerald, opal and pearl with all other gemstones being semi-precious.
Most gemstones are hard. Soft minerals are used in jewelry too, because of their luster that gives them value. Rarity is another characteristic that lends value to a gemstone.
All gemstones, are graded using four basic parameters–the four Cs of connoisseurship: color, clarity, cut and carat weight.
However, there is no universally accepted grading system for gemstones. Diamonds are graded using a system developed by the Gemological Institute of America (GIA) in the early 1950s. Historically, all gemstones were graded using the naked eye. The GIA system included a major innovation: the introduction of 10x magnification as the standard for grading clarity. Other gemstones are still graded using the naked eye (assuming 20/20 vision).
You may have heard of the Mohs scale, which ranks gem and mineral hardness on a scale of 1 (least hard – talc) to 10 (hardest of all – diamond).
Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the counter of a store. Whether the gem is being offered to consumer’s at a traditional jewelry store’s counter, an internet shopping site, or a television broadcast the journey always involves a great deal of effort. Tons of earth and countless hours of labor are needed to being a gem from mine to market.
Throughout history many gemstones have been associated with symbolic significance as well as material wealth and power.
In addition to their use as jewelry, gems were regarded by many civilizations as miraculous and endowed with mysterious powers. Different stones were endowed with different and sometimes overlapping attributes; the diamond, for instance, was thought to give its wearer strength in battle and to protect him against ghosts and magic.
The name “diamond” is derived from the ancient Greek meaning “proper”, “unalterable”, “unbreakable”, “untamed”, “invincible.”
When star-like white rays are seen on a gemstone, it is star effect or asterism. Moreover, star effect is commonly seen on garnet and emeralds.
Gemstones change colors under different lights or radiation. Some gemstones can be fluorescence.
Depending on the mood of the wearer, certain gemstones can change colors. Popular as mood rings in the early Victorian era, mood stones work by reacting to body temperature under varied lightings.
A birthstone is a gemstone culturally associated with the month of a person’s birth. Different cultures have historically used many different sets of birthstones. In 1912, Jewelers of America, a national association of jewelers in the United States, officially adopted the following list, which is currently the most widely used list in the United States and many other countries:
• January: garnet
• February: amethyst
• March: aquamarine or bloodstone
• April: diamond
• May: emerald
• June: pearl, moonstone or alexandrite
• July: ruby
• August: peridot, sardonyx or sapphire
• September: sapphire
• October: opal or tourmaline
• November: citrine or yellow topaz
• December: turquoise, lapis lazuli, zircon, blue topaz or tanzanite