Black gemstones
Hardness. Specific Gravity.
Diamond 10 3.502-3.564
Garnet 6-1/2-7-1/2 3.400-4.500
Jet 3-1/2 1.348
Onyx (a variety
of Chalcedony) 6-1/2 2.598-2.610
Quartz 7 2.670
Tourmaline (not unlike
Black Resin in appearance) 7-1/4 3.024-3.300
Popular articles
- Virtues of Beryl...: Thomas de Cantimpré tells us that the beryl cures quin... | 2 view(s) per day
- Properties of gemstones i...: Properties of gemstones and precious stones used in cry... | 2 view(s) per day
- Virtues of carbuncle...: Many virtues are attributed to carbuncle (red garnet). ... | 2 view(s) per day
- Therapeutic action of pre...: Robert Boyle, writing in 1663, attempts to show that th... | 2 view(s) per day
- Birthstone...: Birthstones have their roots in ancient astrology, and ... | 2 view(s) per day
- Virtues of Agate...: Treating of the medicinal virtues of agates, Pliny dist... | 2 view(s) per day
- Healing stones...: In the sixteenth century sapphires, emeralds, rubies, g... | 1 view(s) per day
- Phenakite to Rock-crystal...: Group E. -Stones whose specific gravity lies between 2.... | 1 view(s) per day
- Hauynite to Opal...: Group F. -Stones whose specific gravity lies between 2.... | 1 view(s) per day
- Crystalline structure...: Before proceeding to the study of precious stones as in... | 1 view(s) per day
