2007-12-13 04:53:36 · 4 answers · asked by heather t 1 in Science & Mathematics ➔ Earth Sciences & Geology
The composition of diamond is carbon (with some impurities to make it black) and the composition of onyx is silicon dioxide. This is the chemistry of both minerals, which is main difference. Any other differences are subjective and are relatively unimportant.
2007-12-13 05:16:58 · answer #1 · answered by Amphibolite 7 · 0⤊ 0⤋
Onyx is hardly ever faceted, let alone faceted the way a diamond is faceted. Onyx has more of a waxy lustre whereas diamond has a metallic sparkle. Onyx is a fairly soft stone and will scratch easily. Even if it was faceted, the facets would wear down in time. Diamond is a lot harder and won't scratch easily.
2016-05-23 09:38:36 · answer #2 · answered by ? 3 · 0⤊ 0⤋
Onyx is a variety of the gem called Chalcedony, which is a cryptocrystalline or microcrystalline quartz. It belongs to the hexagonal crystal systems. Chemical composition is Sio2. Onyx is a chalcedony composed of straight parallel layers of different colors. Black onyx is a misnomer : it is chalcedony with a solid black color and almost always died !
Chalcedony is semitransparant to opaque and comes in virtually all colors.
Diamond is a gem, a mineral species, belongs to the cubic crystal system, and is composed of C (Carbon).
2007-12-14 04:42:17 · answer #3 · answered by Philip H 4 · 1⤊ 0⤋
a black diamond is a jewel, onyx is more of a stone/pebble
2007-12-13 05:03:47 · answer #4 · answered by mushy 5 · 0⤊ 1⤋