chalcedony with curbed or angular bands or layers that differ in color and transparancy
agate
a ca cryptocrystalline quartz aggregate
chalcedony
a property of some crystals that causes them to vibrate at a constant frequency when subjected to an electrical current
piezoelectricity
transparant quartz, usually rock crystal, that contains eye visible inclusions, often named according to the type of inclusions it contains
sagenitic quartz
a type of of sagenitic quartz containing needle-like rutile inclusions
rutilated quartz
a type of sagenitic quartz containing needle-like or rod-like tourmaline inclusions.
tourmalinated quartz
a tablet cut gem with a flat or slightly domed top and sometimes a carved design, typically set in mens rings and cufflinks.
signet
Most gem quality quartz are routinely ___, ___ or ____
heated, bleached, or dyed
the gem trade considers_____ a separate species from large-crystal quartz varieties.
chalcedony
____ is source of finest quality amethyst.
africa
___ is the word's major source of commercial qulaity amethyst
brazil
What quartz is ideal for gem carvers because they're free from flaws??
smoky quartz
what is one of the first gems to be fashioned
chalcedony
____ is one of the most valuable chalcedony varieties
Chrysocolla
collectors often give agates descriptive names based on thier
appearance