Transformation of amorphous calcium phosphate to crystalline dahlite
in the radula teeth of chitons.
The phosphorites are of pelletal type and commonly contain cellophane, dahlite
, francolite, glaucophane, dolomite, iron oxide and pyrite in various proportions.
In this work we have studied a small felsic cupola of the southern part of the CIZ related to two types of mineralizations: i) an intra-granitic D cassiterite-bearing vein-complex, usually related to greisen-like alteration, ii) an exo-granitic Prich ore of hydrothermal apatite (dahlite
)-quartz veins (Vindel et al, 2014; Locutura et al., 2007).
Apatite phase contains 4-8% carbonate by weight, referred to as dahlite
. Mineral composition will vary with age and is always subject to calcium deficiency where carbonate and phosphate ions are in the crystal lattice.