Granite may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from the mantle. However, this proposal has been rejected by
Bohus granite the Lysekil Line. In Norway Iddefjord granite has been a relatively common rock in architecture, further many of the renown statues of Frogner Park in Oslo are made of Iddefjord granite. Iddefjord granite is the official county rock of Østfold in Norway. Geologically the Bohus is a monzogranite, a subtype of granite. Besides the main minerals plagioclase, K-feldspar and quartz the Bohus granites contain lesser amounts of magnetite, apatite, zircon, titanite, garnet and monazite. In restricted areas alteration of the original rock has added prehnite, calcite and chlorite to the mineral assemblage. The texture of the granites varies from fine