quartz and calcedony

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