FORMED by transformation in the existing rocks by the process of metamorphosis. Examples are gneiss, SLATE, marble etc. Igneous rocks are formed by cooling and solidification of magma or lava. Examples include basalt, granite, tuff etc. SEDIMENTARY rocks are formed by deposition and cementation of mineral or organic particles on any water BODY. Examples are sandstone, siltstone etc. Halite is the mineral FORM of the normal salt i.e. sodium chloride.