In many cultures, Jewellery is used as a temporary body modifier
Earrings are form of body modifications, as they are accommodated by creating a small hole in the ear. At Padaung in Myanmar place womenís wear large golden rings around their necks. From as early as 5 years old, girls are introduced to their first neck ring. Over the years, more rings are added. In addition to the twenty-plus pounds of rings on her neck, a woman will also wear just as many rings on her calves too. At their extent, some necks modified like this can reach 10-15 inches long.
In some cases, hooks or even objects as large as bike bars being placed into the recipientís skin. Although this procedure is often carried out by tribal or semi-tribal groups, often acting under a trance during religious ceremonies, this practice has seeped into western culture. Most often, these hooks are used in conjunction with pulleys to hoist the recipient into the air. This practice is said to give an erotic feeling to the person and some couples have even performed their marriage ceremony whist being suspended by hooks. Lip plates are worn by the African Mursi and Sara people, as well as some South American peoples.
Gemstones are so durable
A few are mineraloids not true minerals and are including here: opal, amber, and moldavite. Foremost is durability - it must not easily corrode away, nor can it be brittle. It is so durable that nearly all of the gold ever mined is still in circulation or storage. In some cases, the names are true misnomers, such as Green Amethyst for prasiolite-a transparent green variety of quartz.
In most cases, these variety names are historical, as the gemstones were not recognized as being varieties of other minerals until well after the name was in common use such as aquamarine, emerald, and heliodor as varieties of beryl. And that is related to the third characteristic, ductility. You can see the options are endless and when you are commissioning a piece, why compromise a thing when you can choose!
Gemstones are identified by gemologists
Gemstones are identified by gemologists. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture, and luster. They may exhibit pleochroism or double refraction. Who describe gems and their characteristics using technical terminology specific to the field of gemology.
Next, many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic. They may have luminescence and a distinctive absorption spectrum. For example, diamonds are made of carbon (C) and rubies of aluminium oxide (Al2O3). Another term used is habit, the form the gem is usually found in. For example diamonds, which have a cubic crystal system, are often found as octahedrons.