More information about chalcedony

[PIKAPIKA988]

I am interested in Paloma Picasso''s Sugar stacks rings. They have transparent stones like amethyst, citrine and rubellite etc. and opague stone in chalcedony. I like to know more information about chalcedony. Thanks.

 

[riogems]

It is in the quartz family (but unlike amethyst or citrine in the way it is formed). It can come in a lot of different colors.

 

[C Smith]

Chalcedony is a cryptocrystalline member of the quartz family. It is not made of one crystal as citrine would typically be; it is made of many small crystals. It is readily dyed and comes in darn near any color of the rainbow. Some popular chalcedony forms are aventurine, bloodstone and carnelian. It is very durable in everyday wear in general.

 

[Richard M.]

Since some of these folks may not know the lingo, "crypto" means "hidden." For instance the study of code-breaking (finding hidden messages) is "cryptology." So the word "cryptocrystalline" means that the crystals exist but are too small to be seen by anything but very strong microscopes.

Quartzes are divided into two groups: crystalline and cryptocrystalline. The crystalline types form visible crystals and include so-called Rock Crystal or plain old colorless crystalline quartz; smoky quartz, amethyst, citrine and, rarely, rose quartz which is almost always massive and cryptocrystalline but can form into crystals. Rutilated quartz is simply white crystalline quartz that has grown to engulf sprays of long rutile crystals. There can be many very interesting inclusions in quartz crystals including tourmaline, the iron mineral cacoxenite, chlorite, pyrite, etc.

Cryptocrystalline quartzes are mostly variations on chalcedony. Agate, for instance, is defined as banded chalcedony. Jasper is opaque chalcedony. The classic definition of jasper calls for it to contain iron and be red but usage of the terrm has grown to include many colors. Separating agates from jaspers from chalcedonies can sometimes be a trying task!

Gem chalcedony is generally considered to be translucent evenly-colored gem material. Desirable types include lovely green nickel-colored chryoprase; blue gem chalcedony from Turkey, Namibia, Malawi and California''s Mohave Desert; pink chalcedony; orange chalcedony (sometimes called carnelian); brownish sard; quartz stained by blue-green chrysocolla (usually called ''gem silica''); pink-violet chalcedony from Nevada and Oregon; ''gel'' sugilite, which consists of sugilite-stained red-purple chalcedony; and several other very attractive types. It''s very hard, takes a superb polish and is extremely desirable in its finest forms.

Richard M.