What is Ferrierite?
Ferrierite is a hydrated zeolite-group framework silicate that commonly forms delicate fibrous or radiating crystals in volcanic cavities and altered rocks.
Mineralogy and structure
Reference formula: (Na,K,Ca)2-3MgAl3Si29O72·18H2O. Ferrierite is compositionally variable and can occur as Mg-, Na- or K-dominant material. The structure image uses a sodium ferrierite-type COD model as a representative framework for the guide.
Colour and appearance
Typical colours include colourless, white, pink, yellow, brown. The usual fibrous, prismatic, radiating habit and vitreous, pearly lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Ferrierite forms in or is associated with low-temperature alteration of volcanic rocks, basaltic cavities and hydrothermal zeolite assemblages. Important documented localities include Canada, the United States, India, Japan, New Zealand and Iceland.
Collecting and care
Zeolite crystals are delicate and hydrated; protect from abrasion, acids and strong heating, and handle fibrous aggregates gently.
Ferrierite and the geometry of cavities
Ferrierite is collected for its fine sprays and the way it records open spaces in volcanic rock. The idea of a mineral growing quietly inside a cavity can support reflective or decorative storytelling, but it is not evidence of a special power.
Traditional associations
Ferrierite has no consistent zodiac or birthstone tradition. Any association in a popular guide should be labelled as folklore and may differ between authors.
