Description :
Opal fits into the group of amorphous mineraloids
because, unlike the others mineral gems, its formation is not truly
crystalline. Opal consists of water and hydrated silicon dioxide.
The term opal is derived from a Greek word opallos,
which means “to see changes of color", even though the Romans are believed
to have based their name opalus on the Sanskrit term for precious stone, upala.
Opal is described as a precious gemstone. The opal has been masked in magical
and inscrutability for centuries. It is set spaced out from other gemstones
because of its looks, features and vibrant colors, which vary and spark as you
roll the gem in your hand. No two opals are identical.
Where do they form?
It is an arrangement of non-crystalline silica gel.
Years ago, this silica gel oozes into gaps and cracks of the earth/’s
sedimentary stratum. All the way through eonaeon of time and during nature/’s
heating and shaping processes, the gel toughened and can nowadays be found in
the outward appearance of brilliant opal.
Composition of opal:
Opal has about six to 10 per cent water and consists
of small silica spheres set in a usual prototype.
Composition:Silicon dioxide SiO2nH2O
Crystallization:shapeless.
Structure:enormous; often botryoidally, stalactitic,
etc
Physical Properties:H. = 5.5-6.5. g. = 1.9-2.3. V
Physical Properties :
The water as a component usually presents around three
to ten percent but it can be as elevated as twenty percent. Stones with such
high water percentage are very delicate and smooth to cracking and dryness and
therefore their value is very low. Precious opal gemstones have 4-6% of water.
Opal is a type of gel or semi-liquid material that is formed at relatively low
temperature. They can originate in the fissures or gaps of any type of rocks.
Most generally opal is found in the fissures of basalt, limonite, rhyolite and
sandstone.Mostly Boulder opal occurs in ironstone.
COLOR-Color is root by the usual collection of silica
spheres diffracting white light, and contravention it up into the colors of the
spectrum. The thickness and spacing of the spheres controls the color range.
Clarity- This appealing stone have vitreous to
gleaming shine and is translucent to clear in nature. It consists of enclosures
and blemish just like additional semi precious gemstones. These insertions are
the unconstructive feature hence; get worse the genuine value of the stone.
Cut- It is an extremely vital feature as the beauty of
fundamental feature i.e. color play of the stone is reliant on cut. The cut of
the stone to conclude expose its brilliance. First, the cutters take away the
enclosures there in the stone with the diamond cutting wheel. The trinkets
designers and shopper can get the attractive cut or the shape of this striking
stone.
Carat weight- It is found in lean layers, as huge
pieces are uncommon in nature. After the preliminary gemstone handing out, it
is distorted into a lot of sizes so that it suits the wide-ranging jewelry
designs and also arrives at as numerous people as probable. There are number of
people have the financial limits so they can opt for tiny stone size with a
lesser amount of carat weight.
Natural Occurrence :
Australia , Nevada, Oregon, California, Slovakia,
Mexico