| Brammallite | |
|---|---|
| Brammallite | |
| General | |
| Systematic name | Brammallite |
| Other names | Sodium-Illite |
| Molecular formula | (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] |
| Molar mass | 172.2391 g/mol |
| Appearance | Dark grey-brown fine grained |
| CAS number | ? |
| Properties | |
| Density and phase | ? g/cm³, ? |
| Solubility in water | ? g/100 ml (?°C) |
| Melting point | ?°C (? K) |
| Boiling point | ?°C (? K) |
| Acidity (pKa) | ? |
| Basicity (pKb) | ? |
| Structure | |
| Molecular shape | ? |
| Crystal structure | ? |
| Hazards | |
| MSDS | |
| Main hazards | |
| NFPA 704 | |
| Flash point | ?°C |
| R/S statement | R: ? S: ? |
| RTECS number | ? |
| Related compounds | |
| Other anions | ? |
| Other cations | ? |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Brammallite is a sodium rich analogue Illite.
First found in 1943 in Llandybie, Carmarthenshire, Wales, it is named after British geologist and mineralogist Alfred Brammall (1879-?).
Believed to be a degradation product of paragonite, like Illite it is a non-expanding, clay-sized, micaceous mineral. Brammallite is a phyllosilicate or layered silicate. Structurally Brammallite is quite similar to muscovite or sericite with slightly more silicon, magnesium, iron, and water and slightly less tetrahedral aluminium and interlayer potassium.
The chemical formula is given as (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)][1]
It occurs as aggregates of small monoclinic dark grey-brown crystals. Due to the small size, positive identification usually requires x-ray diffraction analysis.