Gemstone usually found in. For example, diamonds, which have a cubic crystal system, are often found as octahedrons. Gemstones are classified into different "groups", "species", and "varieties". For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Other examples are the emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (yellow) and morganite (pink), which are all varieties of the mineral species beryl. Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture and luster. They may exhibit pleochroism or double refraction. They may have luminescence
Gemstones of Pakistan to their report, 29759 tons of quartz was produced in Mohmand agency in 2003-2004. However, the gemstone sector in the region is not developed and many resources have not been properly identified and exploited. The three mountain ranges of Gilgit-Baltistan; Himalayas, Hindukush, and Karakoram contain many minerals and gems including emerald, ruby, sapphire, aquamarine, moonstone, and amethyst. A number of other minerals are also found in the region such as peridot, tourmaline, topaz, garnet, red spinal, pargasite, diopside, sphene, apatite, azurite, rose quartz, and agate. In Swat, pale green to green coloured emeralds can be found in talc-carbonate schist. In