Stilpnomelane
(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36nH2O
wdx 
edx
thin film 
thin foil
xrf
edx
thin film
thin foil
xrf
Location
Tyllau, Mwn mine Dinas Mawddwy, Dolgellau, Gwynedd
Dana Class
74.01.01.01
Strunz Class
09.EG.40
| Element | WT% |
| Mg | 1.46% |
| K | 1.58% |
| Al | 2.91% |
| Ca | 6.16% |
| Si | 21.24% |
| Fe | 28.08% |
| O | 38.57% |
| Compound | WT% |
| MgO | 2.42% |
| K2O | 1.90% |
| Al2O3 | 5.50% |
| CaO | 8.62% |
| SiO2 | 45.44% |
| FeO | 36.12% |
