We know of corals that are easy to maintain and also those that are not so happy in an artificial aquarium no matter how hard you work to prevent them. We also have talked about the most elegant rare corals that are becoming extinct in a previous post. Surviving in nature might be difficult due to all the climate changes and pollutions. But nature has its own way of safeguarding the creatures. The Gorgonians and anemones live better in natural reefs than in artificial tanks. Some corals grow deeper in the seas and are not within the reach of most aquarists. They are called precious corals and semi-precious corals. They grow at a depth 500 to 1000 feet of water. Their deep hidden habitats have not left these precious corals unexploited. They are used by jewelry making industries and are exploited in large scale for this purpose. These are scarcely available for reef tanks. Only a few places in US harvest them and sell a few species of these deep water corals for non-jewelry making purpose.

Red corals

The most exploited amongst all the precious corals is the red corals. Red corals have durable and deeply tinted red or pink skeleton, which is used for making jewelry. They are also polished and used as gemstone. It is mainly found in deep dark caverns of the Mediterranean Sea. They are stunningly attractive and have branches that are overlaid with soft bright red integument, from where various retractable white polyps extend. Very rarely few of its species are found to be aquaculture. Vase coral is one of its species that can be found in coral selling shops.

Bamboo corals

Not much is known of the bamboo corals that grow in the form of a tree. They have joint-like nodes or axes composed of gorgonin protein. These joints give them a finger like structure similar to bamboo growing on land. The skeleton of this coral is comparatively more porous unlike the other precious corals that have hard skeleton. Mostly colored and filled bamboo corals are sold to aquarists in the name of red corals. Bamboo corals have been found to be of help in the field of orthopedics. They have a long life span but are hard to be found in aquaculture.

Blue coral

Blue corals are reef building corals that do not grow deep into the water but are heavily exploited by the jewelry making industries. They have brighter tint from grey to blue in various species. They are porous and hence filled and stabilized for jewelry making. They produce massive skeleton formed of aragonite. Their Individual polyps live in tubes within the skeleton and are attached by a very thin layer of tissue over the outside of the skeleton. Syrup extracted from the blue coral is normally used in “Bubble Tea” drinks famous in and around south East Asia. Though they are attractive and easy to sustain, it can rarely be found for aquaculture.

Black coral

Black corals or Anthiparian are rare and when polished it shines with amazing luster. This has made its exploitations more intense in jewelry making. Black coral has been listed in Appendix II of the Convention on International Trade in Endangered Species (CITES). Many countries have forbidden the export of these corals. Not all black corals are precious. Antipathes Grandis is the species that finds its use in precious jewelry making mostly in Hawaii.

Sponge corals

They must not be confused with sponges. They are corals with a sponge-like appearance. They are found mainly in the South China Sea, from Taiwan down to Indonesia. Many species of sponge corals have been used for ornamentations for aquarium. Recently some of its precious species have been found to be significant in jewelry making. They are polished to be made smooth for beads or pendants. Their caring is difficult for their porous body and is usually very delicate. They are stabilized and dyed for jewelry creations.

Hawaiian Gold coral

They are found in very few places and grow deeper. Their growth rate is also very low. Hawaiian Gold Coral grows at a rate of approximately 3 inches per year, and only about 3% of the bed can be yielded yearly. Both State and Federal laws strictly regulate the harvest. Amongst all precious corals, Hawaiian Gold Coral is found to be the rarest yet. Their colors vary and so does the pattern of growth. They are found in colors of sandy beige to brown and black. They have a feature called Chatoyance that appears as a glowing light within them. This characteristic is only found in Hawaiian gold corals. Jewelry industry contributes to the exploitation of this rare coral.