A moonstone’s beauty is caused by an optical phenomenon known as adularescence. Light appears to move across the gemstone, giving it a white or bluish glow caused by the scattering of light. Can you name other feldspars that may also show adularescence? http://bit.ly/2AmOHvC | GIA Education

Not tanzanite! This unique stone is a 427 carat unheated Paraíba-type tourmaline rough from Mozambique. How this remarkable crystal is cut will greatly determine its value. It can be heated as a whole crystal before sawing and preforming, which could produce a single Paraíba tourmaline of spectacular size and color. However, the cutter would also run the risk of the gem shattering during heating. It would be safer to cut the crystal into smaller gems and heat the individual gems, but the gems wo

How does GIA confirm diamond origin for our GIA Diamond Origin Report? We use a proprietary method to scientifically match polished diamonds to their original rough of known origin. This matching occurs primarily through measuring spectroscopy, or how a diamond reacts to light. Even if two diamonds have similar color, clarity and dimensions, they will each have distinct spectroscopic properties that can only be read through advanced testing. This is because each diamond has atomic-level crystal

Gia Coppola, un héritage dans le cinéma et la mode