Paper Chromatography Lab Report

Observations of the rock in hand sample have a slight variation to those seen in thin section. In hand sample five main minerals were visible with trace amounts of a sixth seen in very small amounts. Mineralogy in hand sample is k-feldspar, plagioclase, quartz, biotite, magnetite, with trace amounts of hornblende.
Texture (hand sample):
Overall grain size is coarse grained, with a porphyritic texture, non-foliated. The hand sample has a porphyritic texture with pebble sized, euhedral k-feldspar grains and the remaining minerals are generally coarse grained. The overall grain sizes are coarse with an average around 1 mm in size. The k-feldspar grains have rapakivi texture, with the plagioclase surrounding the k-feldspar grains.
Mineral assemblage

Looking at the thin section, a more detailed mineralogy could be

Mineralogy in thin section is more obvious with a total of eight minerals identifiable. K-feldspar, plagioclase, quartz, biotite, chlorite, hornblende, pyroxene, and opaques were identified.
Texture (thin section):
• Overall grain size is coarse grained, with a porphyritic texture due to pebble sized k-feldspar grains, intergranular, non-foliated, myrmekitic texture in the plagioclase grains, undulatory extinction in quartz grains
Mineral assemblage:
• K-feldspar: euhedral grains, rapakivi (overgrowth) texture,
• Plagioclase: subhedral to euhedral grains, polysynthetic twinning; however, the twinning is deformed, myrmekite texture
• Quartz: euhedral to subhedral grains, there are some nice triple junctions but there are also some quartz grains that are sutured; several quartz grains surround larger grains like subgrains, undulatory extinction
• Biotite: subhedral to euhedral grains, some grains are degrading and breaking apart
• Chlorite: subhedral to anhedral grains
• Hornblende: subhedral to anhedral grains
• Pyroxene: subhedral to anhedral grains
• Opaques: anhedral grains; there is no distinct shape, they look like blobs
Mode (thin section):
• 33%