hypersthene

[ hahy-pers-theen ]

Phonetic (Standard)IPA

noun

, Mineralogy.

a dark iron magnesium silicate, an orthorhombic pyroxene containing more than 14 percent ferrous oxide.

hypersthene

/ ˌhaɪpəˈsθɛnɪk; ˈhaɪpəˌsθiːn /

a green, brown, or black pyroxene mineral consisting of magnesium iron silicate in orthorhombic crystalline form. Formula: (Mg,Fe) 2 Si 2 O 6

1800–10; hyper- + Greek sthénos strength, might; replacing hyperstene < French hyperstène

C19: from hyper- + Greek sthenos strength

In the same flow hypersthene-andesite may occur in one portion, while in close proximity the lava is an augite-andesite.

It may be noted also that hypersthene shows a tendency to magmatic alteration, although only rarely.

Both are light colored, and the pleochroism of the hypersthene is sometimes quite faint.

It also surrounds olivine in this same rock, which is a hypersthene-andesite, the hornblende and olivine being only accessory.

Hypersthene is not the prevailing pyroxene, and olivine is usually present, often in such abundance as to make the rock a basalt.

April 25, 2024firkin

[fur-kin ]

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