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
Zoysia 'Emerald' Zoysia 'Emerald' Emerald Zoysia ("Zoysia" 'Emerald') is a cultivar of "Zoysia" grass with a thin bladed leaf that forms a very lush lawn. It shares the drought and shade resistance of the other varieties. This grass has a fine, soft texture and can be left unmowed as it only grows to a height of . When left unmowed, it forms a humpy convoluted surface which is sometimes used in oriental landscapes (see picture on Zoysia page). Emerald Zoysia is adapted to zones 7-11 and does well in warm, humid environments. It is an excellent grass for the southern and southeastern