Rock ID's Flashcards
Granite
Phaneritic, quartz, feldspar, 10% black minerals
Diorite
phaneritic, chunky, reflective. plag and hornblende, 50/50 split black and white
Gabbro
Phaneritic, Dark, visible grains, chunky, 90% dark minerals
Andesite
aphanitic, gray, dull
Rhyolite
aphanitic, light pink, dull
Basalt
aphanitic, black, dull
Rhyolite Porphyry
light pink, dull, a few phenocrysts
Andesite Porphyry
gray, dull, a few phenocrysts
Basalt Porphyry
black, dull, a few phenocrysts
Pumice
holes, floats
Scoria
holes, sinks
Obsidian
glassy, conchoidal fractures
Arkose
detrital, sand sized, quartz and pot. feldspar
Siltstone
detrital, microscopic grains, gritty on teeth,
Breccia
detrital, gravel sized grains, angular grains, ,
Shale
detrital, microscopic grains, fissle, would break
Conglomerate
detrital, rounded gravel,
Quartz Sandstone
detrital, sand sized grains, quartz composition
chalk
fizzes with acid, white
Bauxite
round pebbles (gravel sized), too round for conglomerate, no fizz
Chert
cuts glass, no fizz, microcrystalline, smooth feel, breaks sharply.
Fossiliferous Limestone
fizzes, has gravel sized fossils
Micritic Limestone
fizzes, microcrystalline
Rock Salt
clear, salty taste,