various colors

Is the world's most beautiful and most precious stones, 95% of the world's opal manufacturing in australia. Opal 's chemical composition is SiO2 opal nH2O ( silicon molecules and water mixture ). According to the opal embryoid body color display, it can be divided into colorless, white, light gray, dark gray to black. Unlike other gemstones, opal with charming color is based on the random" chameleon game" to show the spectrum of various colors.
Opal is a gel or liquid silica left into the formation fractures and caves in the deposition of solidified into amorphous non crystal gem mine,University topaz.
which also contains the animal and plant residues, such as trees, shells and bones. In the high grade 5 opal in the moisture can be up to 10%. Usually opal refractive index range from 1.38 to 1.60, Mohs hardness range for 5.5-6.5.
In the opal in the forming process of silica solution, like lava flows into the inland stratigraphic gap and empty ore zone of deposition. Deposition occurs in the ground about forty meters deep, approximately every five million years the sediment will add a cm in thickness. After this phase, a period of two million years with climate change sediment began to slowly solidified. Opal is not binding on other sediments, and after a long time before the hard part.
We usually natural opal is divided into two categories:" plait Xiu Si opal" and" common opal". Plait Xiu Si opal bright color, can appear in full color game, relatively rare and valuable. Dark color, can not show the color game called common opal, common opal found worldwide and produced in small quantities.
In the opal mining out of opal in 95% are all common opal, usually only white, gray or black colour. They are only suitable for" de Bolle opal" and" Chui Bo Lai opal" background stone lining. The remaining 5% are some color grade opal,bring beauty
but 95% of them are just ordinary grade. That is to say, only about 0.25% of the mining amount can be called the true value of the opal.
Plait Xiu Si opal was defined as the color game silicon opal. The term " change the game" is used to describe the precious opal is stunning change opal magic color. The Australian production of opal is sometimes referred to as " deposition " gem " because it is the main form and produced in Great Artesian Basin in Mesozoic sedimentary rocks. Plait Xiu Si opal usually contain 6-10% water, at the same time it contains small silicon particles are arranged in a regular pattern. Its Mohs hardness of 5.5-6.5 in general, according to the different proportion of water content in 1.9-2.3.
Silica condensation process, water gradually reduced, gel form a spherical shape, spherical body natural attachment granular silica,jewelry factory the amorphous silicon particle size in the 1500 to 3500 angstrom ( 1 angstrom is 1/100000000 cm.).
The spheres are small, but was full of opal, is extremely regular arrangement. Because they are round ball, from the structure that has a small gap ( like many marble ball is placed in the container after appearing in the interstices between them ), the space is a three-dimensional arrangement. Opal color as a result of these rules are arranged through the voids optical diffraction effect produced by the decomposition of white light. When the silicon is big time, gap will be relatively large, red or orange diffraction light will appear.
If silicon is small, the same gap will be relatively small, blue purple spectrum by diffraction effects are factored out. The color is like rainbow over changes in general, light diffraction effect is strongest is the largest gap size, so the red color change opal opal surface often very bright, blue, the color change is relatively dim.
In conclusion, plait Hughes opal color changes from regular arrays of silicon particles and the gap between the diffraction effect on white. Silicon particle diameter determines the opal color range, small silicon will usually produce a purple blue opal, otherwise there will be precious red. Every gold OPAL according to their quality has a different value, the key determinants are: embryoid body tone, color, color, brightness of the game; pattern, size and shape.