Identifying Rocks and Textures under the Microscope
slate
a fine grained crystalline rock comprising chlorite and mica
basalt
a mafic, fine grained crystalline rock
dolerite
a medium grained mafic igneous rock
schist
a rock comprising quartz, mica and garnet
oolitic limestone
a rock made of spherical grains of calcite with a calcite cement
chalk
a rock made up of microscopic shells of calcium carbonate viewed under an electron microscope
greywacke
a rock that contains rock fragments, quartz grains and up to 40% clay matrix
well sorted, well rounded
state the grain shape and sorting shown by this sedimentary rock, the largest grain is 1mm in diameter
schistose
Name the texture shown by the mica in this metamorphic rock
gabbro
a coarse grained crystalline rock comprising feldspar and augite
granite
a coarse grained crystalline rock comprising quartz, feldspar and mica
desert sandstone
an arenaceous rock with haematite cement
black shale
an argillaceous rock rich in organic matter
porphyroblast
name for the large garnet crystal in this metamorphic rock
porphyritic
name the texture shown by this mafic igneous rock
equigranular
name the texture shown by this medium grained mafic rock, all the crystals are 1.0 - 1.5 mm in diameter
marble
rock comprising interlocking crystals of calcite, largest crystal is 2mm in diameter
metaquartzite
rock comprising interlocking crystals of quartz, the average crystal size is 2mm
spotted rock
rock formed by low grade contact metamorphism of a clay rich sediment
chiastolite hornfels
rock formed by medium to high grade contact metamorphism of a clay rich sediment