Steudelite

steudelite

sacrofanite

liottite

biachellaite

Images

Formula: Na₃☐(K₁₇Ca₇)Ca₄(Al₂₄Si₂₄O₉₆)(SO₃)₆F₆.4H₂O
Tectosilicate, cancrinite group
Crystal System: Hexagonal
Specific gravity: 2.511 calculated
Hardness: 5
Colour: Colourless
Environments

Volcanic igneous environments

Steudelite is a new mineral, approved in 2021 and to date (February 2023) reported only from the type locality.

Localities

At the type locality, the Biachella Valley, Sacrofano, Metropolitan City of Rome Capital, Lazio, Italy, steudelite was likely formed during late-stage volcanism, either from vapour deposition or by hydrothermal processes (AM 107.1656).
It occurs as thick-tabular, isometric and short-prismatic crystals, up to 7 mm in size in syenite ejecta associated with smectite group minerals, sanidine, sacrofanite, liottite, leucite, haüyne, diopside, biotite, biachellaite and andradite (Mindat).

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