Gems and precious metals are gifts of nature, which need special care. Even though a gem may be millions of years old, once mined and worn, it is exposed to conditions and chemicals that can damage it.
The harder the gem, the less vulnerable it is to potential damage. A diamond, for example, is the hardest gem known to man, and that’s one reason why “it is forever.”
Hardness is based on a gem-trade standard called the Mohs scale, developed in the early 19th century. The scale is structured so that material rated at each higher number can scratch substances with lower numbers. Diamonds are rated the highest, at 10; rubies and sapphires are Mohs 9; emeralds and topaz, 8; and garnets, tourmalines and quartz, 7. Anything softer than a 7 can be scratched, including opal, turquoise, lapis lazuli, coral, pearl.
Gold, silver, and platinum are only Mohs 2-1/2 to 4, which means that they require special care when
wearing, storing, or cleaning. Here are some Do’s And Don’ts: Click to Download Full PDF – 139k