| About Us
| Club Membership Details
| News And Events
| Miners Market
| Forum/Message Board
Colorado Prospector club members -
Click here to find your club membership benefits, links & info.
Chalcedony, a fibrous cryptocrystalline variety of Quartz.
Mohs hardness: 7
Common uses today - stone guitar picks and gemstone cabochons in jewelry.
From Mindat -
"Traditionally defined as a fibrous cryptocrystalline variety of Quartz, more recently, it has been
shown that much Chalcedony is a mixture of Quartz and Moganite, another silica mineral.
When it is concentrically banded (often in rather wild patterns) it is called by the subvariety name Agate.
When it is in flat layers/bands it is called by the subvariety name Onyx.
[Note: Many non-banded forms of chalcedony - such as Moss agate - are often erroneously called 'agates'.
True agate is concentrically banded. Mottled and included chalcedonies are more properly called simply
Petrified wood (agatized wood) is the name given to fossil wood where the replacement of
the wood is by chalcedony, but the banding in this case is due to the wood structure - not concentric
deposition of the chalcedony - and the material is chalcedony, not true agate.]"
Check out the Mindat.org database for more detailed information about
Site Design by Dan and Denise (Owners/Colorado Prospector)