With proper care, citrine is a beautiful and versatile gemstone for jewelry use. – Robert Weldon Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or ...

With a little care, peridot will make a fine gemstone for jewelry. - © GIA & Tino Hammid, courtesy 23rd St. Shoppe, Santa Monica Hardness and toughness Gem and ...

The sample was cut into a gemstone weighing 1.61 carats for further studies. Kyawthuite has an asymmetrical structure and a Mohs hardness of 5.5. It formed deep underground in a pegmatite — an ...