Opal is an authentic colored gemstone, which integrates various colors, giving people a lively and lovely feeling. Opal can be ground into various shapes. Because of its characteristics, it is generally not made into faceted gems, but curved. Even directly made into various shapes.
In terms of chemical composition, opal should be a member of the quartz family, but quartz is a mineral, while opal is amorphous and not a mineral, so it has been independent as a unique gemstone species. The composition of opal is silica and multiple crystal water. The water molecules of opal account for 3% に 20% of its total weight. The higher the content of water molecules, the better the play-of-color phenomenon and the higher the price. それどころか, opals with poor play-of-color have lower prices. The refractive index of opal is about 1.45, the specific gravity is 1.98-2.20, and the hardness is between 5.5 そして 6.5, but the toughness is poor, so opal is easy to break due to collision, so be careful when wearing it.
The play-of-color phenomenon is the most fascinating charm of opal. This phenomenon makes opal have a variety of colors, and the color will flash with the movement of opal. This is because opal’s tiny particles make light diffract. As a result, when the silica particles are arranged more neatly, the play-of-color area presented by the opal is larger and the play-of-color is also more obvious. The play-of-color phenomenon is the soul of opal and the most important factor in determining the price. Red play-of-color is the most expensive. If red play-of-color is more and more flexible, the price is even higher than diamonds.
The earliest opal origins were in the Czech Republic and Hungary. After the 19th century, Australia became the largest opal exporter. The newer origins are Brazil, グアテマラ, Honduras and Mexico. The fire opals are mostly produced in Mexico.