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
Aquamarine Power University, Belfast, led by Professor Trevor Whittaker. The Queen's University, Belfast studies were co-funded by the Engineering and Physical Sciences Research Council and Allan Thomson, who had previously founded and led the UK’s first commercial wave energy company, Wavegen. In 2005, Allan Thomson founded Aquamarine Power to progress the commercialisation of the Oyster device. In 2007 Scottish & Southern Energy subsidiary Renewable Technology Ventures Limited invested in Aquamarine with a further investment in 2010. In February 2009, Aquamarine Power and Queen's University, Belfast signed an agreement to extend their R&D partnership to 2014. In February 2009, Aquamarine Power signed an