Topaz is a common gemstone. It is available in Yellow, Blue, Green, Pink, Purple, White, Brown, Orange, Grey, and Red. This gem has a vitreous luster, meaning glass as appearance. It also has a orthohombic crystal system. On the Mohs Hardness Scale, it is on the 8 scale, near defining mineral (10). This gemstone's pleochroism is weak in thick sections.