Formula: Cu(UO₂)₂(PO₄)₂ · 8H₂O

Species: Phosphates

Colour: Pale green to dark green

Lustre: Sub-Adamantine, Sub-Vitreous, Resinous, Waxy, Pearly

Hardness: 2½

Specific Gravity: 3.52 – 3.70

Crystal System: Tetragonal

Member of: Meta-autunite Group

Name: Named in 1916 by Arthur Francis Hallimond in honor of Torbern Olof Bergman (1735–1784, Sweden) and for “meta” for its lower hydration level and its relationship to torbernite.

Co-Type Localities: Schneeberg, Erzgebirgskreis, Saxony, Germany, Redruth, Cornwall – England, UK

A secondary mineral resulting from the weathering/dehydration of Torbernite. Crystals can be either cloudy and dull or translucent and glassy.