Contoh feldspar

• This is conspicuous for biotite and amphibole crystals but less so in the strongly altered feldspar crystals.

• In these first five zones, some crystals, mainly feldspars, are visible in hand specimen.

• The presence of quartz-filled microcracks in feldspar crystals suggests that deformation continued during cooling and crystallization.

• Such spidergrams strongly suggest that these metafelsites solidified from highly fractionated melts, which underwent extensive, low pressure, accessory phases- and feldspar-dominated crystal fractionation.

• It is a medium-grained, foliated orthogneiss with small feldspar 'augen'.

• Some feldspar grains, however, show weakly developed asymmetric strain shadows (-type).

• The magnetic fraction of the surface sand contains pyroxene and feldspar grains as in the bulk material, but little quartz.

• The two planes intersect along cd which is the locus of liquids in equilibrium with a silica polymorph + two feldspars + aqueous fluid.

• The matrix is composed of finegrained recrystallized feldspar.

• Feldspar porphyroclasts have been rotated during shearing and folding.