| Paederos
term for opal used by the Romans
Painted lady
field term for fracture surface of rock
coated with precious opal
Paleozoic
geologic era from ...
Pantherus
a term sometimes used for opal in the Middle
Ages
Phytolith
relict fragment, commonly opaline silica,
from decomposition of organic material,
especially plants
Plant opal
opaline silica deposited in plant tissue
during growth
Playa
dry lake bed
Pliosaur
marine animal which lived in the Cretaceous
period
Polymorphs
compounds of identical chemical composition,
but different crystal form
Porcelanite
siliceous rock of fine texture and smooth
fracture
Potch
term applied in the opal fields to non-precious
opal
Pozzolana
natural materials which set like cement
when mixed with lime and water
Puddling
miners term for breaking down clay and soft
rock to extract opal |
