| Biogenic
formed by living organisms
Birefringence
property of most crystalline materials which
enables them to rotate the plane of polarisation
of polarised light.
Blower
machinery used to extract mullock when mining
for opal
Boulder opal
precious opal which occurs in ironstone
concretions, especially in Queensland.
Breakaway
dissected desert country, especially north
of Coober Pedy |
