Bannisterite

Field of view: 10 mm. A vein of bannisterite. The brown vein from left ot right at the middle is bannisterite. Micaceous bannisterite crystals are vertical to the vein wall, and exhibit perfect cleavage in a direction. The white zone at the bottom of bannisterite vein is quartz. The massive pale pink parts at the upper right are rhodochrosite. The massive brown part at the lower half of this specimen is aggregate of fine caryopilite and quartz crystals with some thin quartz veins.

Recovered from a chert-hosted bedded manganese deposit subjected to Pumpellyite-Actinolite facies metamorphism.

Bannisterite from this location was described in 1981.