Class: Phosphates, arsenates, vanadates
Group: Metavariscite
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).
Chemistry
FePO4·2H2O
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).
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’