Nontronite
Na0.3Fe3+2(Si,Al)4O10(OH)2 • nH2O [CNMNC approved formula]
Named after its locality: Nontrone, Dordogne, France.
| IMA status : | Approved Species 1827 () |
| CLASSIFICATION | |
| Dana (8th edition) : |
71.03.01a.03 |
| (71) Phyllosilicate Sheets of Six-Membered Rings | |
| (71.03) with 2:1 clays | |
| (71.03.01a) Smectite group (Dioctahedral Smectites) | |
| Nickel-Strunz (10th edition) : |
09.EC.40 |
| (09) Silicates | |
| (09.E) Phyllosilicates | |
| (09.EC) Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets | |
| Crystal system: | Monoclinic System |
| Point group (H-M): | 2/m — prismatic |