"This stone is a man made aurora borealis opal. It has very interesting multicolored color play that reminds me of a galaxy inside. The pendant is made with sterling silver and the stone is set in a bezel setting. NOTE: As with all opal, this is a soft stone so care will need to be taken to not scratch or damage it. Always remove your jewelry prior to washing and showering. Jewelry should always be the last thing you put on after applying makeup, perfume, hairspray, etc. Never wear soft stone jewelry while working out, or to bed, as this my cause unnecessary wear and tear and my damage the stone. Total length of the pendant is 38mm (approximately 1.5\"). Width is 28mm (approximately 1.13\"). When purchasing you have the option to purchase the pendant only or with your choice of chai