Mineralpedia Details for Matulaite

Named to honor Margaret Mary Matula from Pennsylvania, USA who was the provider of some of the initial specimens. Matulaite is a rare mineral that can be found in the United States, Germany, Portugal, and France. It occurs as a secondary mineral in oxidized phosphatic iron deposits. Associated minerals include beraunite, rockbridgeite, dufrenite, cacoxenite, strengite, wavellite, goethite, and hematite.

 Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/matulaite.pdf

Formula

CaAl₁₈(PO₄)₁₂(OH)₂₀·28H₂O 

Crystal System

Monoclinic 

Cleavage

Perfect, None, None 

Luster

Pearly 

Color

colorless, white 

Streak

white 

Class

Monoclinic - Prismatic 

Hardness

1 

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White, pearly, spheroidal crystals, which in cross-section are shown as thin platy crystals in fan-like, full and partial radial patterns to about 0.75mm across. Often single plates give sericitic-like reflections.

Tiny, less than 0.3mm, pearly white, equant micro crystals.

Dull white spherical Matulaite crystals to about 0.3mm on and with yellow Jahnsite blades. Also associated are very tiny, thin yellow Laueite crystals in an 1.3 x 5mm vug. A rare mineral which occurs in both pegmatitic and non-pegmatitic environments like many other Ca-Al phosphates.