History & Introduction
The coral gemstone is a quality variety of natural coral and is closely related
to reef-building 'stony' coral. The coral stone that is valuable is a deep water
coral that is formed in rocky sea beds, which possess low levels of sedimentation,
naturally in dark environments of over 500 feet deep adding up to caverns and crevices.
Coral is gradually built by very small marine animals called coral polyps. Such
small soft-bodied creatures created by with minute, hard shells that accumulate
as the colony grows. With time, the colony is formed to complex branches and skeletal
structures composed with hardened calcium carbonate, and coloured by carotenoid
pigments.
Maximum coral gemstones available currently, are varieties of Corallium rubrum,
a very specific pink to red colour species of the coral genus. In the trade, there
are times when Corallium rubrum is referred as 'noble coral' and is considered to
be the coral highest in demand jewelry. Noble coral even includes the famous 'angel
skin coral', a pink to salmon colour coral. Corallium rubrum, along with fossil
coral, coral sand, agatized coral and coral fragments are not regulated or protected
from international trade that means it is possible to import and export to maximum
countries without permits.
There are more than 2,500 varieties of corals in nature that are distinguished as
the palette of 350 colours. Originally, they are dim, however they receive strong
glass glitter that is polished; coloration it is both uniform and patchy. When polyps
and "fleshy" skin is removed, a coral is used like pearls and goes for the manufacture
of various interior decorations and jewellery.
In Europe corals are a symbol of modesty. As per legends and beliefs, they guard
from witchcraft and poisons, are advantageous against breathlessness, forgetfulness,
loss of appetite, nervous tic, and nerve attacks. Corals provide strength to heart
and reduce heart palpitations, it cures sadness. These semi-precious stones are
also used to treat eyes. Ancient Greeks considered the pink coral as a symbol of
immortality and happiness.
During middle period it was said that corals formed a man wise, prevented trouble,
healed wounds and lowered fever and even to be successful in relations with the
opposite sex. It is even believed that by burning and sprinkling on the old ulcers,
then you can dry them, remove cancerous growths: corals heal and purify them so
that there will be no trace. It helps to avoid hatred, envy and anger; for that
it needs to be worn as a ring on the middle finger of the right hand. Ancient Romans
thought that burned, pounded and dropped in water corals gives relief to people
who are suffering from spasmodic pain intestine, in diseases of the stomach, bladder
and spleen.
Coral, was classed with precious gems and was found adorning ancient amulets with
emerald, pearl, diamond and ruby, and also it was proved experimentally by the sixteenth
century to cure madness, provide wisdom, to cure the flow of blood from a wound.
It was also popular to prevent sterility.
Coral lost its popularity for a while, however it again steadily start gaining popularity
in these years. This material is from semi-translucent to opaque material created
a colony of marine invertebrates, is mainly a skeletal calcium carbonate gem. The
formation as seen in the water look like tree branches. Coral gemstone is available
in a wide range of colours. It is one of the most expensive varieties and has becomes
very popular in recent years and is used widely for jewellery purposes. At present,
the rarest and the most expensive variety found is blood coral, even famous as noble
or oxblood coral. This variety is very deep red.
It is a very a soft stone, so some precautions are taken when wearing it. Due to
its calcium composition, you must be careful to avoid contact with acid like the
vinegar in a salad that you might toss your hands.
Recognise - Coral is an organic material and it is a soft stone
so it not a durable gemstone. It has hardness from 3 to 4 on the Mohs scale that
is easily helpful to discern and identify coral from alike gemstones like carnelian,
rhodonite or spessartite garnet. Red and white coral with a composition of calcium
carbonate has a specific gravity or density from 2.60 to 2.70 and even the refractive
index from 1.486 to 1.658. These specific gemmological properties, combined with
coral's translucent to opaque form, it easy to recognize natural coral gemstone
from imitations or similar gemmy materials.
Availability - Although we get precious coral gemstone from locations
all around the world, Torre del Greco (near Naples, Italy) is said to be the top
coral trading centre for over 200 years, processing nearly 75% of the entire world's
supply of coral. Maximum valuable coral available today is harvested from the western
Mediterranean Sea, particularly in Sardinia. Notable deposits are also found in
the Red Sea, the Malaysian Archipelago, the Taiwan, the Bay of Biscay, Midway Islands,
Japan, Australia and the Hawaiian Islands. The valuable coral found in Hawaii, coastal
Japan, the Mediterranean and the Red Sea is considered to be the finest coral at
present.
Usages - Coral gemstone is used as beads and cabochons. It is even
sculpted into small carvings like flowers for pins and brooches. At times the tiny
branches of Coral are stranded into spiky, dangling necklaces. Hawaiian golden coral,
black ("akkabar", or "royal coral") coral, blue ("acorea") coral, red and pink precious
corals are particularly treasured in a jewellery production. Corals have been a
favourite decoration since ancient times. Maximum the red varieties are in used.
Buying Guide
Colour - The valuable coral stone naturally shows a range of warm
pinkish to red colours that includes light-red to salmon (momo coral) with medium-red
(Sardegna coral) to deep ox-blood red (moro coral); colour is said to get fade after
it is worn. Noble coral consist of the most desirable uniform colour, but it displays
streaks or spots of white to pinkish red, particularly angel skin coral. This gemstone
is also found in other colours like blue, gold, black and white. Gold colour coral
from Hawaii is tremendously rare and highly in demand due to its slight chatoyancy.
Blue and black coral gemstone is not often used for gems or jewellery as its trade
is heavily regulated.
Clarity and Lustre - Naturally the stone is translucent to opaque.
After it is unworked, it consist of naturally dull, matte lustre. Polished coral
shows an attractive vitreous lustre. Coral stone is polished with emery as well
as fine-grain sandstone, and then with felt-wheels it is finely polished.
Cut and Shape - Due to its softness and opacity precious coral
is mainly cut en cabochon. It is generally used for sculptures, beads, ornamental
and carvings. Cabochons is found in just about any shape, however the most post
shapes it is found are ovals, rounds and free-form shapes.
Treatment - Natural coral is not treated, however there are materials
that are dyed to get a more valuable colour. There are a variety of other materials
used to imitate coral, like glass, bone, plastic and conche pearl.
Gemological Characteristics: