Hunting in Chantaburi Gem Market 2010-08-23

About Topaz 2010-07-20

Topaz is a silicate mineral of aluminium  and fluorine  with the chemical formula Al2SiO4(F, OH)². Topaz crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces. Pure topaz is colorless and transparent but is usually tinted by impurities; typical topaz is wine, yellow, pale gray or reddish-orange, blue brown. It can also be made white, pale green, blue, gold, pink (rare), reddish-yellow or opaque to transparent/translucent.

About Opal 2010-07-20

Opal is a mineraloid gel which is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl and basalt. The word opal comes from the Latin opalus.

About Ruby 2010-07-20

A ruby is a pink to blood-red gemstone, a variety of the mineral corundum  (aluminium oxide). The red color is caused mainly by the presence of the element chromium. Its name comes from ruber, Latin for red. Other varieties of gem-quality corundum are called sapphires. The ruby is considered one of the four precious stones, together with the sapphire, the emerald, and the diamond.

About Sapphire 2010-07-19

Sapphire is a gemstone  variety of the mineral corundum, an aluminium oxide (α-Al2O3), when it is a color other than red, in which case the gem would instead be a ruby. Trace amounts of other elements such as iron, titanium, or chromium  can give corundum blue, yellow, pink, purple, orange, or greenish color. Pink-orange sapphires are also called padparadscha.