Rossmanite

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Formula: ☐(Al₂Li)Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)
Cyclosilicate (ring silicate), tourmaline group
Crystal System: Trigonal
Specific gravity: 3.00 measured, 3.06 calculated
Hardness: 7
Streak: White
Colour: Pale pink to colourless
Environments

Pegmatites

Rossmanite occurs in granitic pegmatites hosted by biotite and hornblende gneiss (Webmin).

Localities

At the Virorco pegmatites, Las Águilas deposit, El Trapiche, Coronel Pringles department, San Luis Province, Argentina, rossmanite generally occurs as sub-millimeter crystals in contact with schorl or elbaite. Primary elbaite-rossmanite has been partially replaced by iron-rich tourmaline. Some crystals contain multiple species of tourmaline such as rossmanite, schorl and dravite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

Northeast of Eibenstein an der Thaya, Raabs an der Thaya, Waldviertel, Lower Austria, a single crystal of rossmanite was found in a pegmatite where only a marble quarry now remains (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Koktokay No. 3 pegmatite, Altay Mine, Koktokay pegmatite field, Fuyun county, Aletai Prefecture, Yili Hasake Autonomous Prefecture, Xinjiang, China, rossmanite occurs in an albite variety cleavelandite-spodumene zone as thin veinlets within the main mass of elbaite crystals (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At the type locality, the Rožná pegmatite, Rožná, Žďár nad Sázavou District, Vysočina Region, Czech Republic, rossmanite was discovered in the albite-lepidolite unit of a pegmatite hosted dominantly by biotite gneiss with wide-spread intercalations of hornblende gneiss of the amphibolite facies. Rossmanite occurs as euhedral crystals enclosed in fine-grained lepidolite and associated with schorl, elbaite, dravite and foitite. The lepidolite sub-unit is dominated by lepidolite with abundant albite and elbaite, with accessory apatite, topaz, beryl, amblygonite - montebrasite, columbite-(Mn) and cassiterite (AM 83.896-900, http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Laštovicky, Rousměrov, and at Dobrá Voda, both in the Žďár nad Sázavou District, Vysočina Region, Czech Republic, rossmanite was found in a lepidolite pegmatite as crystals to 1 cm in lepidolite associated with schorl and elbaite. Elbaite-rossmanite is the last tourmaline to crystallise (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Radkovice, Hrotovice, Třebíč District, Vysočina Region, Czech Republic, rossmanite was found in a lepidolite pegmatite with schorl and elbaite, in the K-feldspar zone and in the lepidolite core (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

In the pegmatites at Sant'Ilario in Campo, Campo nell'Elba, Livorno Province, Tuscany, Italy and San Piero in Campo, Campo nell'Elba, Livorno Province, Tuscany, Italy, rossmanite occurs as a colourless portion of the crystals beneath the black foitite caps of tourmaline formerly identified as elbaite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At tha Anjahamiary pegmatite, Tranomaro, Amboasary Sud, Anosy, Madagascar, tourmaline occurs as small, multicolored crystals. The bluish portion of the crystals is liddicoatite and the pinkish portion is rossmanite. The tourmaline occurs with feldspar variety amazonite, smoky quartz, mica and albite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Ågskardet, Holandsfjorden, Meløy, Nordland, Norway, colour-zoned tourmaline is found in an elbaite-rich pegmatite. The crystal studied has an interior that is fluor-elbaite, with a rim of fluor-liddicoatite grading to a calcium-rich fluor-elbaite. In one area of the crystal there is a sodium-free area corresponding to rossmanite as well as regions in thin veins that are rossmanite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Nyköpingsgruvan, Utö Mines, Utö, Haninge, Stockholm County, Sweden, in pegmatites, during crystallisation tourmaline composition evolved from aluminium-rich schorl through elbaite and phases intermediate between elbaite and rossmanite to calcium-bearing elbaite-rossmanite and finally to calcium-bearing elbaite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At the Dorothy China Clay Pit, Whitemoor, St Stephen-in-Brannel, Cornwall, England, UK, in lithium-mica granite, rossmanite occurs in an unusual sample of tourmaline-quartz veinstone that contains a number of different tourmaline species. These represent the final crystallisation products of a complex sequence that saw foitite form early, followed by schorl, fluor-schorl, elbaite and rossmanite (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Mount Mica Quarry, Paris, Oxford County, Maine, USA, portions of elbaite crystals grade into rossmanite. The black caps are foitite and directly under the foitite caps is where the rossmanite is usually found (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Black Mountain Quarry, Rumford, Oxford County, Maine, USA, elbaite and rossmanite occur in the outermost zones of the pegmatite. The rossmanite occurs as crystals in a lepidolite pod (http://minerals.gps.caltech.edu/rossmanite/Index.htm).

At Newcomb Township, Essex county, New York, USA, rossmanite occurs as a rim on uvite. The tourmalines occur in marble with albite, quartz, graphite, tremolite and olenite (http://minerals.gps.caltech.edu/rossmanite/Index.htm, R&M 84.4.366).

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