Dickinsonite Value, Price, and Jewelry Information

Dickinsonite

This mineral is seldom even mentioned in the gem literature because it is so rare and has been so seldom cut. Faceted gems are practically nonexistent, and would be among the rarest of all cut stones.

Dickinsonite Information

Data Value
Name Dickinsonite
Colors Oil green, olive green, yellowish green, brownish green, brownish.
Crystallography Monoclinic. Crystals tabular, pseudorhombohedral; foliated, micaceous, radiating.
Refractive Index 1.648-1.671
Luster Vitreous; pearly on cleavage.
Hardness 3.5 - 4
Fracture Uneven
Specific Gravity 3.38-3.41
Birefringence 0.013-0.014
Cleavage Perfect and easy, 1 direction
Dispersion Strong
Stone Sizes Very tiny green gems, less than 1-2 carats, have been cut from Connecticut material.
Luminescence None observed.
Luminescence Present No
Transparency Transparent to translucent.
Absorption Spectrum Not diagnostic.
Formula

H2Na6(Mn,Fe,Ca,Mg)14(PO4)12 · H2O.

Pleochroism

Pale olive green to pale yellowish green.

Optics

= 1.648-1.658; β = 1.655-1.662; γ = 1.662-1.671. Biaxial (+), 2V ~90°.

Optic Sign Biaxial +

 

Optics= 1.648-1.658; β = 1.655-1.662; γ = 1.662-1.671.

Biaxial (+), 2V ~90°.

Occurrence: A secondary phosphate mineral in granite pegmatites.

Branchville, Connecticut; Portland, Connecticut; Poland, Maine.

Comments: This mineral is seldom even mentioned in the gem literature because it is so rare and has been so seldom cut. Faceted gems are practically nonexistent, and would be among the rarest of all cut stones.

Name: After the Rev. William Dickinson in recognition of his interest in the locality where first found.