Alteration product of basalt and similar eruptive rocks.
IMA Status:
Valid Species (Pre-IMA) 1801
Locality:
Bodenmais in Bavaria, Germany. Link to MinDat.org Location Data.
Name Origin:
From the Greek harmos - "I combine" and temseis - "I cut" alluding to the fact that the pyramid divides parallel to the plane that passes through the terminal edges.