Hydroxymcglassonite-(K)

hydroxymcglassonite-(K)

meieranite

yuzuxiangite

sugilite

Images

Formula: KSr₄Si₈O₂₀(OH).8H₂O
Phyllosilicate (sheet silicate), apophyllite group
Crystal system: Tetragonal
Specific gravity: 2.60 measured, 2.614 calculated
Hardness: 4½ to 5
Streak: White
Colour: Colourless
Solubility: Insoluble in water and hydrochloric acid
Environments

Hydrothermal environments

Hydroxymcglassonite-(K) is a new mineral, approved in 2020 and to date (April 2023) has been reported only from the type locality.

Localities

At the type locality, the Wessels Mine, Hotazel, Kalahari manganese field, Northern Cape, South Africa, has been found associated with meieranite, sugilite, aegirine, pectolite, and yuzuxiangite. The is colourless and transparent with a white streak and a vitreous lustre (AM 107.9.1818-1822).
It was found on a typical green sugilite specimen that is also the type sample for meieranite. Hydroxymcglassonite-(K) crystals are found intergrown with isolated blue granular meieranite aggregates that are embedded in a matrix consisting of mainly massive pale green sugilite, along with minor prismatic grey aegirine, bladed white pectolite and fibrous pale brown yuzuxiangite. Hydroxymcglassonite-(K) crystals are granular, less than 0.05 mm in size (R&M 98.1.94-98).

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