Massive. Original hexagonal mineral of Berzelius and Haidinger, probably [Tysonite] (q.v.).
G = 5·7-5·9. H = 4. Reddish yellow; opaque.
Österby, Sweden.
Freyalite.
Silicate of E and Th, with Al, Fe, Mn, Na, aq., etc. Cer = 31·3; ThO₂ = 28·4; ZrO₂ = 6·3%.
Amorphous.
G = 4·06-4·17. H = 6. Brown; opaque; lustre resinous.
Brevig, Norway.
Gadolinite.
FeO, 2BeO, Y₂O₃, 2SiO₂, where Y = yttrium metals. Cer = 3·4-51·5 (usual 6-20); Yttr = 5-60 (usual 35-48)%.