Niigataite (original) (raw)

Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 8.890(4) Å, b = 5.5878(18) Å, c = 10.211(4) Å
β = 115.12(3)°

Ratio:

a:b:c = 1.591 : 1 : 1.827

Unit Cell V:

459.26 ų (Calculated from Unit Cell)

Morphology:

anhedral grains

General Appearance of Type Material:

Micro anhedral grains to 0.5 mm across, intimately intergrown with clinozoisite, diaspore and chlorite.

Place of Conservation of Type Material:

National Science Museum in Tokyo, and in the Fossa Magna Museum, Itoigawa, Niigata, Japan.

Geological Setting of Type Material:

Prehnite-rich rodingite block derived from serpentinite melange. Unlike the other Sr-bearing silicates from this district, niigataite has not been found in the jadeitite boulders.

Associated Minerals at Type Locality:

Reference:

Miyajima, H., Matsubara, S., Miyawaki, R., Hirokawa, K. (2003): Niigataite, CaSrAl3(Si2O7)(SiO4)O(OH): Sr-analogue of clinozoisite, a new member of the epidote group from the Itoigawa-Ohmi district, Niigata Prefecture, central Japan. Journal of Mineralogy and Petrology Science, 98, 118-129.