Physical Properties of Chalcedony

Identification

• Chalcedony is a type of quartz whose crystals are too small to be seen by the naked eye. Jasper, bloodstone, onyx, carnelian, flint and chert are all types of chalcedony.

Color

• Chalcedony comes in many colors, mostly red, black, purple, green, turquoise, yellow, orange and brown. Agate varieties of chalcedony are banded with many visible colors.

Shapes

• Chalcedony is usually found in smooth, round or ovular forms that resembles pebbles.

Hardness and Streak

• On Moh's scale--which ranks the hardness of minerals from the softest, talc, at one to the hardest, diamonds, at 10--chalcedony is considered a seven. When chalcedony is scratched against a surface, it creates a white streak.

Luster and Transparency

• Chalcedony ranges from transparent to opaque. The luster of chalcedony ranges from vitreous or glassy to waxy to even dull.