Dumortierite, Dehesa, San Diego County, California

Here is another rarity we recently came across: dumortierite! The chemical formula for this borosilicate probably gives mineralogy students nightmares, although it certainly is a pretty mineral. Our specimen showcases radiating, lavender crystal sprays up to 2 cm in diameter contrasting nicely against matrix. This is our finest specimen from a lot obtained from our friend, the late Mike Clark (and likely self-collected by him decades ago). Dimensions:  6 cm x 7 cm x 10.5 cm