Pargasite was found to occur in druse of hornblende bearing augite hypersthene dacite rock from Ishikami-yama near the west of Kumamoto city with colourless tridymite and grain of white cristobalite.
Morphological study about this pargasite was discussed in detail in 1935 by Ryuji Sugiyama. Experimental specimens of pargasite had collected for over three years and its quantity was about 3gr. in weight.
This pargasite has the following optical properties:α=1.6324-1.6326, β=1.6340-1.6343, γ=1.6504-1.6507, 2V=(+)63°-64°. Colour is brownish yellow and its pleochroism is strong in thin section. X=yellowish green, Y=bluish green, Z=greenish brown.
The result of chemical analysis is given in the Table 2. It is charac teristic of chemical analysis is given in the Table 2. It is characteristic of its chemical constitution that this pargasite is the high, content of alkalis, especially in K₂O. MgO and sparing in iron oxides. The writer presumes that this is related to its production state by autopneumatolytic action. The formula of this pargasite showed by, W. L Bragg's one is (OH·F)_1.6(Ca·Na·K)_2.8 (Mg.Fe'''·Fe''Mn·Ti·Al)_4.5 (Si.Al)₈ O₂₂.