A very good example of this rare calcium manganese beryllium silicate. Trimerite occurs as subhedral, prismatic, yellow-orange crystals to 3mm along the margin of a calcite veinlet in manganite ore. The largest, and most significant, nearly complete crystal (3 mm) is marked with a red arrow. From Langban, Filipstad, Varmland, Sweden. Ex. Swedish Natural History Museum collection with label.