Borates, Tungstates & Rare Groups

What Defines the Rare Groups Group

Smaller mineral groups that each contain only a handful of well-known species. Borates include howlite and ulexite (the television stone). Tungstates include scheelite and wolframite, the ores of the highest-melting metal. Molybdates (wulfenite) and chromates (crocoite) round out these uncommon but visually striking mineral families.