Onyx is a variety of the microcrystalline quartz, chalcedony. It is similar to agate, but it has straight rather than curved bands. These may be brown and white or black and white. It is carved as small a sculpture and intaglio, or may be polished, tumbled, or cut as beads. Onyx is popular as an excellent material for inlay work.
Since ancient Egyptian times, onyx has been stained to improve or change its color. Much onyx has been produced by soaking agate in a sugar solution, then heating it in sulfuric acid to carbonize the sugar particles. It is commonly carved as small a sculpture and intaglio, or may be polished, tumbled, or cut as beads.
Onyx was used as a seal, an ornament popular with the Romans by exposing the straight layers of to a dramatic effect.
Onyx stone is commonly found with opal in the mother rock. Polished onyx stone can be used as slabs in restaurants and kitchens. It displays parallel bands of different colors.
Occurrence
Onyx is found in many countries around the world. It is formed by deposition of silica in gas cavities in lava. That gives the stone is characteristic band.
Onyx Properties
- Specific Gravity: 2.61
- Refractive Index: 1.53-1.54
- Birefringence (DR): 0.004
- Luster: Vitreous
- Crystal Structure: Trigonal
- Composition: Silicon dioxide
- Hardness: 7
Crystals Directory
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
W
Y
Z
Birthstone
January
February
March
April
May
June
July
August
September
October
November
December
