biotite
1
9.9
A dark brown to black mineral that forms thin shiny sheets in many rocks
- noun
- /ˈbaɪəˌtaɪt/
- Specialized
:
biotita
- In the granite rock, you can see shiny flakes of biotite alongside quartz and feldspar.
- biotite and hornblende
- quartz-biotite
- biotite crystals
Examples
-
Quartz-biotite pseudomorph after orthopyroxene in a granodiorite from the I-type Budduso pluton in Sardinia, Italy.
Academic text (2018) -
Geologists often examine biotite to understand the conditions under which the rock formed.
-
Black biotite crystals are frequently found in metamorphic rocks, giving them a distinctive shimmer.
Surface Forms
Morphology
biotite = Biot (semi-transparent) = biot + ite
The formation Biot + -ite clearly marks a mineral name (the suffix '-ite' signals a mineral), but the base is a personal name and does not convey the mineral's properties to learners.
Etymology
The word biotite is named for the French scientist Biot. The ending -ite is a common part in mineral names meaning 'stone' or 'mineral', so the name means 'Biot's mineral'.