Tholeiitic Basalt

Tholeiitic Basalt

HA-14

Hand Sample: Aphanitic medium gray vesicular basalt with scattered olivine crystals. Olivine crystals are commonly growing either in clusters or as one single crystal. Vesicles are found throughout sample and range in diameter from 0.05cm to 2cm.

Thin Section: Groundmass composed of plagioclase grains and glass. Sample contains plagioclase phenocrysts with elongate shape as well as numerous olivine phenocrysts.

Sample collected January, 1969

Western Minerals

Southern end of Mauna Loa - Island of Hawaii
Sample collected on highway

1887