Type Occurrence of Vermiculite
| Place Of Occurrence | – | Millbury, Worcester Co., Massachusetts, USA |
| Year Of Discovery | – | 1824 (18th Century) |
| Occurrence | – | Forms as an alteration product of biotite or phlogopite, by weathering or hydrothermal action. Vermiculite is mined as a natural insulation material worldwide. |
Crystallography of Vermiculite
| Crystal System | – | Monoclinic |
| Cell Parameters | – | a = 5.24Å, b = 9.17Å, c = 28.6Å, β = 94.6° |
| Ratio | – | a:b:c = 0.571 : 1 : 3.119 |
| Unit Cell Volume | – | V 1,369.83 ų (Calculated from Unit Cell) Vermiculite for Crystallography Radiation – Copper Kα ;Horizontal Axis: 5° to 90° ; Vertical Axis: 100% |
Optical Data of Vermiculite
| Type | – | Monoclinic |
| RI values | – | n α = 1.525 – 1.561 nβ = 1.545 – 1.581 nγ = 1.545 – 1.581 |
| Maximum Birefringence | – | Δ = 0.020 Vermiculite for Crystallography Chart shows birefringence interference colour range (at 30�m thickness) and does not take into account mineral colouration |
| Surface Relief | – | Low |
| Dispersion | – | Weak |
X-Ray Powder Diffraction
 |
||
| Radiation | – | n α = 1.525 – 1.561 nβ = 1.545 – 1.581 nγ = 1.545 – 1.581 |
| Data Set | – | Near Tonapah, Nevada, USA 1796 |
| Data courtesy of RRUFF project at University of Arizona. | ||
Powder Diffraction Data |
||
| d-spacing | Intensity | |
| 14.15 | – | (10) |
| 4.57 | – | (6) |
| 2.615 | – | (5) |
| 2.570 | – | (5) |
| 2.525 | – | (4.5) |
| 2.380-2.365 | – | (3.5b) |
| 1.528 | – | (7) |
Classification of Vermiculite
| IMA status | – | Valid – first described prior to 1959 (pre-IMA) – “Grandfathered” |
| Strunz 8th edition ID | – | 8/H.21-10 |
| Nickel-Strunz 10th (pending) edition ID | – | 9.EC.50 9 : SILICATES (Germanates) E : Phyllosilicates C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets |
| Dana 8th edition ID | – | 71.2.2d.3 71 : PHYLLOSILICATES Sheets of Six-Membered Rings 2 : Sheets of 6-membered rings with 2:1 layers |
| Hey’s CIM Ref | – | 16.19.22 16 : Silicates Containing Aluminum and other Metals 19 : Aluminosilicates of Fe and Mg |
Relationship of Vermiculite to other Species
| Structurally related to group(s) | – | Montmorillonite-Vermiculite Group |
| Related Minerals – Nickel-Strunz Grouping | – |
| Related Minerals – Nickel-Strunz Grouping | ||
|---|---|---|
| 9.EC.05 | Minnesotaite | (Fe,Mg)3(Si4O10)(OH)2 |
| 9.EC.05 | Talc | Mg3(Si4O10)(OH)2 |
| 9.EC.05 | Willemseite | (Ni,Mg)3(Si4O10)(OH)2 |
| 9.EC.05 | Ferripyrophyllite | Fe23+(Si4O10)(OH)2 |
| 9.EC.05 | Pyrophyllite | Al2(Si4O10)(OH)2 |
| 9.EC.05 | Boromuscovite | KAl2(BSi3O10)(OH)2 |
| 9.EC.05 | Celadonite | K(Mg,Fe2+)Fe3+(Si4O10)(OH)2 |
| 9.EC.05 | Chernykhite | (Ba,Na)(V3+,Al,Mg)2((Si,Al)4O10)(OH)2 |
| 9.EC.05 | Montdorite | (K,Na)2(Fe2+,Mn2+,Mg)5(Si4O10)2(OH,F)4 |
| 9.EC.05 | Muscovite | KAl2(AlSi3O10)(OH)2 |
| 9.EC.05 | Nanpingite | CsAl2(AlSi3O10)(OH,F)2 |
| 9.EC.05 | Paragonite | NaAl2(AlSi3O10)(OH)2 |
| 9.EC.05 | Roscoelite | K(V3+,Al)2(AlSi3O10)(OH)2 |
| 9.EC.05 | Tobelite | (NH4,K)Al2(AlSi3O10)(OH)2 |
| 9.EC.05 | Aluminoceladonite | K(Mg,Fe2+)Al(Si4O10)(OH)2 |
| Related Minerals – Nickel-Strunz Grouping) | ||
|---|---|---|
| 16.19.1 | Indialite | Mg2Al3(AlSi5O18) |
| 16.19.2 | Cordierite | (Mg,Fe)2Al3(AlSi5O18) |
| 16.19.3 | Sekaninaite | (Fe,Mg)2Al3(AlSi5O18) |
| 16.19.4 | Ferrogedrite | Mg3(Si4O10)(OH)2 |
| 16.19.5 | Staurolite | (Fe2+,Mg,Mn)2Al4Si2O10(OH)4 |
| 16.19.6 | Chloritoid | Mg3(Si4O10)(OH)2 |
Other Names for Vermiculite
| Synonyms | – | BrodrickiteCulsageeiteJefferisiteZonolite |
| Other Languages | – |
| Other Languages | |
|---|---|
| German | Vermiculit |
| Russian | Вермикулит |
| Simplified Chinese | 蛭石 |
| Spanish | Vermiculita |