Eclogite is a dense, green plutonic rock composed of coarse grains of green, sodium-rich pyroxene (omphacite) and pale pink, magnesium rich garnet (almandite and pyrope); kyanite and rutile are also common. Chemically, an eclogite is equivalent to basalt. It occurs as small bodies or blocks that appear to have been formed in the lowermost crust and upper mantle, where igneous and metamorphic processes merge. Most eclogites shows signs of retrogressive metamorphism, with the pyroxene and garnet crystals separated by rims of hornblende and plagioclase that have developed from the reaction between these crystals. Common minerals are: garnet, quartz, omphacite pyroxene, and sometimes kyanite, phengite, paragonite, zoisite, dolomite, and corundum.