Basalt is an igneous rock, consisting of augite and triclinicfeldspar, with grains of magnetic or titanic iron, and also bottle-green particles of olivine frequently disseminated. It is usually of a greenish black colour, or of some dull brown shade, or black. It constitutes immense beds in some regions, and also occurs in veins or dikes cutting through other rocks. It has often a prismatic structure as at the Giant's Causeway, in Ireland, where the columns are as regular as if the work of art. It is a very tough and heavy rock, and is one of the best materials for macadamising roads. Research Basalt
Olivine is a group of minerals characterised by their green colour, the typical
olivine has the formulae (Mg,Fe)2SiO4 and a relative hardness of 7. It's name is derived from the characteristic olive green colour. A common rock forming mineral. A clear green variety is called peridot and has some uses as a gem.
Olivine minerals are hard and resistant to heat, and are used as abrasives and refractory sands. Research Olivine
Peridotite is an intrusive igneous rock thought to be one of the major components of the Earth's mantle. Peridotite is generally dark coloured and formed from dense, heavy minerals, of which more than 40 percent are olivine. Research Peridotite
Abbreviations
Research Basalt
