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Silicate

Plombièrite

Ca₄Si₆O₁₆(OH)₂(H₂O)₂·(Ca·5H₂O)
Hardness4
Crystal systemMonoclinic
ClassSilicate
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Plombièrite specimen

White acicular crystals of the rare mineral plombièrite, from Bazhenovskoe Deposit, Asbest, Urals Region, Russian Federation. — Photo: David Hospital · CC BY-SA 4.0

Plombièrite

Plombièrite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₄Si₆O₁₆(OH)₂(H₂O)₂·(Ca·5H₂O).

It crystallizes in the monoclinic crystal system (space group Bb). It is a member of the Tobermorite structural group.

Key properties: Mohs hardness 4; specific gravity 2.02–2.2; optically biaxial.

IMA symbol Plm, IMA status: approved, named in 1858.

A gelatinous substance which hardens in air, formed from thermal waters (Plombiµeres, France); a natural gel formed from hydration of bredigite and larnite at a diabase-chalk contact (Ballycraigy, Ireland).

It is found associated with Zeolites (Plombiµeres, France).

The name refers to the French locality at Plombiµeres.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more P minerals or help write this entry.