Pumpellyite Prehnite Basaltic Tuff Breccia

Title

Pumpellyite Prehnite Basaltic Tuff Breccia

Alternative Title

Pumpellyite

Identifier

TMJ-15

Description

Rock Sample:
The color is mainly a very dark green to dark grey. Some parts of the rock exhibit greasy luster. There are some tannish white spots and some slightly larger dark brown spots. The tannish white mineral reacts with acid. There are dark green and faded dark green phenocrysts(~3mm in size). There are medium to coarse grained white phenocrysts (2-10mm). Some phenocrysts touch each other with no matrix in between. There are some areas that possess a dark grey matrix. There are many fractures through out the sample. It has a rough and bumpy texture overall.

Thin Section:
There are many micro-fractures and veins. There are many larger fractures as well. There are also circular crystals that have a pointed center. Some of the augite crystals are severely fractured, and have quartz veins running through the fractures. There are many elongated quartz crystals that are curved. There is some glass intergrown into the circular crystals.
-Matrix (55%)
-Augite (25%)
-Quartz (10%)
-Plagioclase (10%)
-Magnification at 4x/0.10

Date

1969

Contributor

Western Minerals, Inc.

Spatial Coverage

Tanzawa Mountains, Japan Northern edge of (Zone III)

Temporal Coverage

N/A

Accrual Method

Purchased from Western Minerals Inc.

Unit

Pumpellyite prehnite basaltic tuff breccia

Number of Thin Sections

1

Geolocation