This part of ISO 710 provides a unified series of symbols and abbreviations for the representation of certain minerals often found in rocks, with a view to facilitating the characterization of certain rocks on detailed maps, plans and geological crosssections. In general, there are two ways of representing these minerals, namely — by the addition of another symbol, characterizing the mineral, to the elementary symbol for the rock in question; — by the addition of letters, designating the mineral, to the symbol for the rock.