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
Geology of Pakistan emerald, rare-earth minerals bastnaesite and xenotime, sphene, tourmaline, and many varieties and types of quartz. The Pakistan Mineral Development Corporation is the responsible authority for the support and development of the mining industry. Gemstones Corporation of Pakistan looks after the interests of stake holders in gemstone mining and polishing as an official entity. Baluchistan province is the richest in mineral resources available in Pakistan. While recently Sindh discovered coal deposits in Thar. Khyber Pakhtunkhwa is rich in gems. Most of the mineral gems found in Pakistan exist here. Apart from oil, gas and some mineral used in nuclear energy purposes