Talk:Bluestone

The more valuable variety of bluestone (sodalite) is called hackmanite and is hard enough to hold facets without cracking. Hackmanite exhibits tenebrescence or reversible photochromism, that is, the ability to change color when exposed to sunlight. The photo in the main article shows a high quality hackmanite gemstone before and after exposure to sunlight for five minutes. The stone changes from a very pale violet to dark violet when "charged" by the sun. The effect is completely reversible by taking the stone out of strong light. If bluestone is found in loot or treasure, the more valuable variation can be considered hackmanite and treated as a semi-precious stone or even a fancy stone. Moviesign 03:30, September 21, 2011 (UTC)