This is a volcanic breccia from the farm Murrelfontein adjacent to the contact with the gabbro unit. It includes partially melted glass and tridymite, a high temperature polymorph of quartz, and has a brecciated appearance. The breccia has a allotriomorphic- granular texture and is holocrystalline. Coarse, anhedral, chaotic-looking dark black crystals (3-12mm) are surrounded by slightly lighter colored, smaller anhedral crystals (2 mm -6 mm). There are trace olivine phenocrysts (2 mm).
No date given.
Western Minerals, Inc.
Is Part Of
Karoo- Birds River, Eastern Cape, South Africa
183-179 Ma (Jurassic)
Purchased from Western Minerals, Inc.
Number of Thin Sections