Chalcedony jewelry has become very popular in recent years.
This cryptocrystalline quartz is very common and was perhaps used by early man
to create tools and weapons. Within this family there are many other varieties
offering a huge diversity of patterns and colors. Chalcedony jewelry is often
made from the unstained quartz material that is grayish blue to purple in
color. Chalcedony jewelry that has been stained by other oxides is called jasper.
Banded varieties, or materials with mosslike inclusions, are known as agate.
Often, chalcedony jewelry features cabochons and beads. The agate form can be
carved into cameos or ornamental objects.
Because this cryptocrystalline quartz is so abundant, there
are many other colors of chalcedony jewelry available in the marketplace.
Carnelian is a variety that may be red, orange-red or brown in color. Heating
can turn almost any chalcedony red since it contains compounds that oxidize
when heated. Other common forms of solid-colored chalcedony are onyx, sard,
plasma, bloodstone and flint. Each of these varies in color from green to
black to white and red.
Chalcedony jewelry can also be created from the patterned,
mosslike variety known as agate. Banded agates have regular color layers and
bright colors. The moss agates have mossy inclusions of mineral oxides. There
are several other varieties including scenic, lace, fire, shell and Turritella
agate.
Moh's scale of hardness lists chalcedony as having a hardness
of 6.5-7. It is not recommended that chalcedony jewelry be cleaned with
abrasive jewelry cleaner, but rather with a polishing cloth.
