Table 7.
Assumed reference (simplified, idealized) formulae for common phyllosilicates in modal analyses of meteorites
| Chrysotile | Mg3(Si2O5)(OH)4 |
|---|---|
| Berthierine | (Fe2+,Fe3+,Al)3(Si,Al)2O5(OH)4 |
| Cronstedtite |
(Fe2+Fe3+)3(Si,Fe3+)2O5(OH)4 iron end; but usually contains some Mg: (Mg, Fe)3Si2O5(OH)4 |
| Saponite–serpentine | Mg3(AlxSi4-xO10)(OH)2·4H20, x ~ 0.33 |
| Saponite, general formula | (Ca0.5|Na)0.3(Mg|Fe2+)3(Si|Al)4O10(OH)2·4 H2O [232] or Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2·n(H2O), typically 3:1 for Si:Al and 1:1 or 1:2 for Mg:Fe, thus (next line) |
| Saponite ‚typical ‘ | Ca0.25MgFe2Si3AlO10(OH)2·4(H2O), molar mass 451.2613 + n·18.0153 g·mol−1 |
| Saponite (Orgueila) | (Mg2.55Fe2+0.45)(Si3.46Al0.54)O10(OH)2·nH2O (n≈4 if fully hydrated) |
| Serpentine (Orgueila) | (Mg2.55Fe0.45)Si2O5(OH)4 (no crystal water) |