crystals of heulandite-(Ca), crystals of mordenite : Mahodari, Nashik District (Nasik District), Maharashtra, India — Photo: Parent Géry · CC BY-SA 3.0
Heulandite
A zeolite series once a single species — split in 1997 into Ca, Na, K, Sr and Ba members — forming handsome pearly crystals in basalt cavities.
Intro adapted from Wikipedia (CC BY-SA).
Heulandite is a mineral group, with the chemical formula (Ca,Na)₂Al₂Si₇O₁₈·6H₂O.
It crystallizes in the monoclinic crystal system.
Key properties: Mohs hardness 3.5–4; typically white or pink or red or colorless.
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Index entry. This entry combines official IMA/RRUFF species data with published physical-property data and a Wikipedia introduction — a full written entry hasn’t been published yet.
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