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Fine Jewelry University

1. 

   Gem in the Spotlight: Tourmaline

   FJU Category: Gemstones | Tags: Colored Gemstones, Folklore, Gem Spotlight, Gemology, Jewelry History, Tourmaline

   …unlike emerald and aquamarine, for example, which are members of the beryl family). It has a refractive index of 1.624 to 1.644 and a Mohs hardness of 7 to 7.5 which makes it softer than topaz or sapphire and harder than tanzanite or … a long trend of confusing tourmaline with other gems. Another notable example of this is the “Caesars Ruby,” the 255ct stone in the Russian crown jewels that has been traded between France, Russia, and Sweden for centuries. It was …

2. 

   Gem in the Spotlight: Quartz

   FJU Category: Gemstones | Tags: Amethyst, Citrine, Gem Spotlight, Gemology, Onyx, Prasiolite, Quartz

   … refractive index at 1.54-1.55 and is doubly refractive. It has a vitreous polish luster and its specific gravity is 2.66 (may vary based on inclusions). In addition to its beauty, quartz is also an extremely useful stone due to its … likewise, when induced with an electrical charge, the crystal will vibrate at a very precise interval of exactly 32,768 vibrations/second or ~32kHz. This property is utilized in various electronic devices such as quartz watches and …