Tetragonal; pseudomorphous.
G = 3·9-4·1. H = 6. Brown, often dull white internally.
Hitterö, Norway; Haute Loire, France; and in U.S.A.
Mauzeliite.
Very similar to [Lewisite] (q.v.), with Pb. TiO₂ = 8%.
Cubic.
G = 5·11. H = 5-6. Brown; translucent.
Jakobsberg, Sweden.
Melanocerite.
Very complex fluosilicate of E and Ca, chiefly. Cer = 48; Yttr = 9·2; ThO₂ + ZrO₂ = 2%.