- Tiburon Peninsula, Marin Co., California, USA
- Cabinet, 11.4 x 6.9 x 3.8 cm
Lustrous, black glaucophane prisms are festooned on all sides of the gneiss matrix of this fine cabinet specimen from Marin County, California. Glaucophane is an uncommon amphibole group mineral and is found in low to medium temperature metamorphic terrains. It is relatively common in California, but is seldom seen in old-time, quality specimens, such as this. Ex. Mullane Collection.