Biotite
K(Mg,Fe)3AlSi3O10 (OH)2
wdx 
edx
thin film 
thin foil
xrf
edx
thin film
thin foil
xrf
Location
Bancroft, Ontario, Canada
Dana Class
71.02.02b.02
Strunz Class
09.EC.20
| Element | WT% |
| Ti | 1.65% |
| K | 8.43% |
| Al | 8.84% |
| Mg | 8.88% |
| Fe | 14.47% |
| Si | 17.31% |
| O | 40.41% |
| Compound | WT% |
| TiO2 | 2.76% |
| K2O | 10.15% |
| Al2O3 | 16.71% |
| MgO | 14.73% |
| FeO | 18.62% |
| SiO2 | 37.03% |
