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Class: Phosphates, arsenates, vanadates
Group: Metavariscite

Typically an alteration product of triphylite in zoned complex granite pegmatites (Anthony et al., 2001—2005).

Original description: ‘Phosphosiderit’ Bruhns, W., Busz, K., 1890. Phosphosiderit, ein neues Mineral von der Grube Kalterborn bei Eiserfeld im Siegenschen — Zeitschrift für Krystallographie und Mineralogie 17: 555—560 [view in ‘Library’].

Type locality: Kalterborn mine, Siegen, North Rhine-Westphalia, Germany.

Type material: unknown.

Etymology: from phosphorus and the Greek for iron in the composition.

Distribution: Argentina; Brazil; Canada; France; Germany; Liberia; Mozambique; Portugal; South Africa; Sweden; USA (Anthony et al., 2001—2005).



Essential elements: hydrogen (H), oxygen (O), phosphorus (P), iron (Fe).

Crystal data

Crystallography: monoclinic — prismatic. Crystal habit: as crystals, tabular on {010}, to stout prismatic [001], with prominent {010}, {110}, {001}, {011}, many others, to 2.5 cm; may be radial fibrous, in botryoidal or reniform crusts and masses. Twinning: on {101}, common, typically as interpenetrations (Anthony et al., 2001—2005).

Physical properties

Cleavage: on {010}, good; on {001}, indistinct (Anthony et al., 2001—2005). Fracture: uneven (Anthony et al., 2001—2005). Tenacity: no data. Hardness: 3.5—4 (Anthony et al., 2001—2005). Density: 2.74—2.76 g/cm3 (Anthony et al., 2001—2005). Luminescence: none.

Optical properties

Colour: reddish violet, reddish purple, yellow-orange, may be dark blue, moss-green to nearly colourless; typically rose-red to colourless in transmitted light (Anthony et al., 2001—2005). Diaphaneity: transparent to translucent (Anthony et al., 2001—2005). Lustre: vitreous to subresinous (Anthony et al., 2001—2005). Refractive index: 1.692—1.739 — anisotropic [biaxial (-)] (Anthony et al., 2001—2005). Birefringence: 0.046. Dispersion: very strong (Anthony et al., 2001—2005). Pleochroism: X = pale rose-red; Y = carmine-red; Z = colourless (Anthony et al., 2001—2005).

Material from ‘Repository’

2 specimens: 0605 — 5.16 ct, no locality data; 0606 — 5.00 ct, no locality data.

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