A poorly defined material, found as infillings in cavities in basic igneous rocks, possibly an altered chlorite.
A poorly defined material, found as infillings in cavities in basic igneous rocks, possibly an altered chlorite.
An obsolete varietal term for biotite.
A dioctahedral member of the true mica group. The ideal end-member formula is KCrMg□(Si4O10)(OH)2 where □ = vacancy. First discovered at the Srednyaya Padma U-V deposit, chromceladonite was described from southern Karelia, Russia, in occurrences relating to apparent metasomatism and in association with dolomite, calcite, hematite, quartz, roscoelite, chromphyllite, uraninite, zincochromite, vanadium oxides and selenides (Pekov et al., 2000). Chromceladonite occurs as a 1M polytype.
Cf., chromphyllite
An obsolete term for chromian muscovite, chromian phengite.
An obsolete term for chromian muscovite, chromian phengite.
An obsolete term for chromian muscovite.
A dioctahedral member of the true mica group. The ideal end-member formula is KCr2□AlSi3O10(OH,F)2, where □ = vacancy. Chromphyllite, like muscovite, occurs as the 2M1 polytype in C2/c symmetry, and the Cr forms a solid solution series with Al in muscovite. Chromphyllite is known from the Lake Baikal region, Russia, Outokumpu, Finland, and elsewhere, and is believed to occur in association with metasomatism.
Cf., muscovite
An obsolete term for clintonite.
A member of the serpentine group with textures showing packets of cylinders, scrolls, and tubes, as well as helical or spiral fibers. Chrysotile, ideally Mg3Si2O5(OH)4, crystallizes in monoclinic symmetry (clinochrysotile) with the fiber axis parallel to X and orthorhombic symmetry with the fiber axis along X (orthochrysotile) or Y (parachrysotile). Polytype stacking for clinochrysotile is either 2Mc1 or 1Mc1, where the number of layers (e.g., 1 or 2) precedes M = monoclinic, subscript c = cylindrical, and subscript 1 is used to distinguish the form from another cylindrical polytype that would otherwise have the same symbol. The orthochrysotile polytype is 2Oc1. Cylindrical structures do not have consistent hydrogen bonding between layers that would be observed in an ideal platy structure, and thus do not conform to the standard polytypes. Fiber dimensions are variable with inner diameters near 70-80 Å and outer diameters reported at 220-270, >350, and 490 Å (the latter value involves synthetic samples). Al, Fe2+, and Fe3+ may substitute for Mg, and Fe3+ may substitute for Si; all substitutions are very limited, but greater than in lizardite. The differences between these substitutions in lizardite vs. chrysotile suggest that in natural systems, lizardite and chrysotile are not sensu stricto polymorphs. Chrysotile, or “white asbestos”, is the asbestosform serpentine and is mined in Russia near the Ural Mountains and in Asbestos, Quebec, Canada.
Substances that close a wound by scar formation; substances that heal (e.g., by healing clays).
Syn., cicatrize