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Inorganics

Id Identification Type Name Description Distinguishing Features Tags
107 Mineral Albite Clear to pale yellow. Nonpleochroic. Low birefringence. Euhedral laths possible in volcanic settings, generally subrounded/subangular in shape. High relief. Can be distinguished from quartz by its 90 degree cleavage. Polysynthetic (albitic, simple) twinning is diagnostic. Sodium endmember of plagioclase solid solution series.

See also feldspar.

"Elongate prisms in multiple domains" -Smoot
polysynthetic-twinning feldspar
silicate
plagioclase
21 Mineral Amphibole Transparent colorless to green, brown, red, yellow, depending on mineralogy within the amphibole group. Strongly pleochroic. Moderate birefringence may be masked by color. Anhedral to euhedral prismatic grains. High relief. Hornblende-series minerals the most common detrital amphiboles. Pleochroic
Subhedral
Prismatic
ferromagnesian
high-relief
green
silicate
transparent
green
62 Mineral Apatite Usually transparent colorless. Nonpleochroic. Weak birefringence (white-gray). Prismatic, six-sided crystals may be euhedral or subhedral. Moderate relief. May occur as either detrital grains (derived from felsic igneous rocks) or authigenic/diagenetic crystals in phosphate-rich environments. Prismatic
Moderate-relief
Colorless
Transparent
low-birefringence
anisotropic
euhedral
phosphate
heavy-mineral
37 Mineral Aragonite Transparent colorless. Nonpleochroic. Extreme birefringence. Distinguished by small (~10 um) acicular (needle-like) or rice-like grain morphology. Moderate relief, varying by direction. Twinning may be common.

Organisms such as pteropods, most mollusks, and some corals produce biogenic aragonite.
Rice-shape
Acicular
Elongate
High-birefringence
Carbonate
salt
transparent
colorless