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
Emerald Lingam Lord Budha (Devanagari: बुध ) (Tamil: புதன்) is considered as the god of the planet Mercury. According to Hindu mythology Lord Budha is considered as one among the nine Navagrahas. He represents green color and gemstone emerald. He is also the god of merchandise and protector of merchants. He is of Rajas Guna and represents Communication. as well as the Navagraha. Puranas recommend to worship the gemstone in the form of Siva Lingam. The kings and emperors considered that the statues carved using emerald stones have divine power. They also considered that the emerald stone is free from faults (doshas).