Strontiojoaquinite (original) (raw)

RI values:

_n_α = 1.710(2) _n_β = 1.718(2) _n_γ = 1.780(3)

2V:

Measured: 35° to 45°, Calculated: 42°

δ = 0.070

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Optical Extinction:

X:a = 19°; Y = b, Z = c.

Comments:

X = Y (colorless) < Z (yellow).

Comments:

Absorption X = Y < Z

Crystal System:

Monoclinic

Cell Parameters:

a = 10.516(6) Å, b = 9.764(5) Å, c = 11.87(1) Å
β = 109.28(8)°

Ratio:

a:b:c = 1.077 : 1 : 1.216

Unit Cell V:

1,150.44 ų (Calculated from Unit Cell)

Morphology:

Steep bipyramids with forms {111} and {110} and truncated with a small basal face {001}.

Twinning:

Submicroscopic twinning.

Comment:

Point Group: 2; m; or 2/m: ; Space Group: P 2; Pm; or P 2/m:

General Appearance of Type Material:

Steep bipyramidal crystals to 1 mm.

Place of Conservation of Type Material:

1. University of California, Santa Barbara, California, USA.
2. Harvard University, Cambridge, Massachusetts, USA, 119526.
3. National Museum of Natural History, Washington, D.C., USA, 149429.

Geological Setting of Type Material:

Metamorphosed basalt, included as a tectonic block within the a serpentine body. The basaltic was subjected to high pressure metamorphism, and to considerable compositional modification by fluids during the emplacement of the peridotite and serpentinization.

Associated Minerals at Type Locality:

Reference:

Wise, W.S. (1982) Strontiojoaquinite and bario-orthojoaquinite: two new members of the joaquinite group. American Mineralogist: 67: 809-816.