Mineral Names:

Bismutite, Bi₂O₂(CO₃). A product of alteration of native bismuth and bismuthinite, occurring uncommonly in the quartz zone and the quartz-lath spodumene zone. Dark gray to blue-green to yellow in color, typical occurring with beyerite. Original bismuth or bismuthinite may no longer be present. Original x-ray diffraction confirmation was made by Heinrich (1947), and he also reported that the bright yellow bismutite contained 0.05 wt. % CuO and the bright green bismutite had more than 1.0 wt. % CuO. Aggregates of the fine-grained bismuth mineralization typically are less than 5 cm in diameter, although the Bi mineral staining along cracks and grain boundaries can extend outward over a larger area.

Beyerite, (Ca,Pb)Bi₂O₂(CO₃)₂. A product of alteration of native bismuth and bismuthinite that occurs with bismutite uncommonly in the quartz zone and the quartz- lath spodumene zone.
Bismuthinite, Bi₂S₃. Primary Bi mineral from which the beyerite and bismutite are derived. Reported by Jahns and Ewing (1976). Bismuth, Bi. Primary Bi mineral from which the beyerite and bismutite are derived, reported by Heinrich (1947).

Eucryptite, LiAlSiO₄. Very fine-grained eucryptite intimately intergrown with quartz occurs at the base of the quartz-lath spodumene zone, replacing spodumene. The eucryptite is typically massive and granular, white, with a waxy luster. It can be difficult to distinguish from spodumene in hand-sample. However, under short-wave ultraviolet light eucryptite fluoresces a begonia-rose color. Mrose (1952) gives a chemical analysis, measured cell contents are Li_4.5Al_5.3Si_6.9O₂₄, optical properties and x-ray powder diffraction data. In weight % the chemical analysis is 8.36 Li₂O, 0.19 CaO, 0.62 Na₂O, 0.38 K₂O, 35.76 Al₂O₃, 54.64 SiO₂, 99.95 Total. Chakoumakos and Lumpkin (1990) show in thin-sections the textural relationship of the eucryptite + quartz replacing spodumene crystals. [INSERT LINK TO MICROGRAPH HERE] The eucryptite + quartz pseudomorphism of spodumene according to the lithium aluminosilicate equilibrium phase diagram (London 1984) is driven by decompression during uplift and erosion of the consolidated pegmatite (Chakoumakos and Lumpkin 1990, London and Burt 1982).

References:

Heinrich, E. W. (1945) Bismuth minerals in Colorado and New Mexico pegmatites (abstract).

Heinrich, E. W. (1946) Bismuth minerals in Colorado and New Mexico pegmatites (abstract). American Mineralogist 31, 198.

Heinrich, E. W. (1947) Beyerite from Colorado. American Mineralogist 32, 660- 669.

London, D. (1984) Experimental phase equilibria in the system LiAlSiO₄ - SiO₂ - H₂O: a petrogenetic grid for lithium-rich pegmatites. American Mineralogist 69, 995- 1004.

London, D. and Burt, D. M. (1982) Lithium aluminosilicate occurrences in pegmatites and the lithium aluminosilicate phase diagram. American Mineralogist 67, 483-493.

Mrose, M. (1952) The a-eucryptite problem (abstract). Geological Society of America Bulletin 63, 1283.