Blood or red coral is the common name given to Corallium rubrum and several related species of marine coral.
The distinguishing characteristic of precious corals is their durable and intensely colored red or pink skeleton,
which is used for making jewelry.
Red corals grow on rocky seabottom with low sedimentation, typically in dark environments—either in the depths
or in dark caverns or crevices. The original species, C. rubrum (formerly Gorgonia nobilis), is found mainly in
the Mediterranean Sea. It grows at depths from 10 to 300 meters below sea level, although the shallower of these
habitats have been largely depleted by harvesting. In the underwater caves of Alghero, Sardinia (the "Coral Riviera")
it grows at depth from -4 mt to -35 mt. The same species is also found at Atlantic sites near the Strait of Gibraltar and at
the Cape Verde Islands.Other Corallium species are native to the western Pacific, notably around Japan (Corallium japonicum)
and Taiwan;these occur at depths of 350 to 1500 meters below sea level in areas with strong currents
Coral as a gemstone
The hard skeleton of red coral branches is naturally matte, but can be polished to a glassy shine.It exhibits a range of
warm reddish pink colors from pale pink to deep red; the word coral is also used to name such colors. Owing to its intense
and permanent coloration and glossiness,
Precious coral has relative density of 3.86 and hardness 3.5 on the Mohs scale. Due to its softness and opacity, coral is usually
cut en cabochon, or used to make beads.
At the beginning of the 1st millennium, there was significant trade in coral between the Mediterranean and India,
where it was highly prized as a substance believed to be endowed with mysterious sacred properties. Pliny the Elder
remarks that, before the great demand from India, the Gauls used it for the ornamentation of their weapons and helmets;
but by his period, so great was the Eastern demand, that it was very rarely seen even in the regions which produced it.
Among the Romans, branches of coral were hung around children's necks to preserve them from danger, and the substance
had many medicinal virtues attributed to it. The belief in Coral's potency as a charm continued throughout the Middle
Ages and even early in 20th century Italy it was worn as a protection from the Evil eye, and by women as a cure for Infertility.
1.In Hindu astrology red coral is associated with the planet Mars or Graha-Mangala and used for pleasing Mars.
It should be worn on the ring finger.
2. A branch of red coral figures prominently in the civic coat of arms of the town of Alghero, Italy.
3. Used in Marken en Volendam as costume jewelry