Class : Silicates
    Subclass : Phyllosilicates
    Crystal System : Monoclinic
    Chemistry : (Ca_0.5,Na)_0.3Al₂(Si,Al)₄O₁₀(OH)₂ nH₂O
    Rarity : Common

Beidellite is a hydrated phyllosilicate from the smectite group. It is a naturally white clay which is most often colored pink to brownish, or grey-pink ; it presents itself like most clays in earthy, compact and unctuous masses. It owes its name to its place of discovery : Beidell (Colorado, USA). Beidellite is a silicate weathering mineral that typically forms through the weathering of basic and ultrabasic igneous rocks, but can also result from the hydrothermal weathering of plagioclases in hydrothermal deposits, including copper-bearing porphyries. Beidellite is, along with montmorillonite and saponite, one of the main constituents of bentonite.

Main photo : Beidellite from Cameron, Arizona, USA © Chris Emproto

No known twin for this mineral species.

No fake or treatments identified for this mineral species, but difficult to identify without heavy laboratory equipment.