Some Facts about Turquoise and Coral Jewelry

There are several scales that are used by Gemologists to determine hardness, durability or the scratch resistance of gemstones. The one that is most widely recognized is the Moh scale, which is really a table that indicates the scratch resistance of gemstones. A German minerologist by the name of Friedrich Moh developed a scale in 1822 to gepare the scratch resistance of gemstones. It has begee universally known as Moh's scale, with Diamond being a 10 or the most scratch resistant to Talc at a 1, which is the least scratch resistant.I bring this up because most gemstones are enhanced in one way or another to increase durability, reduce scratch resistance or improve the look of the stone, or to even create a new look. For example, Carnelian can be heat-treated to produce that dark, rich reddish-orange color as found in some of the beads pictured below.