HAWAII ROCKS and minerals Oceanite from Mauna Loa

HAWAI‘I ROCKS (and minerals)

Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine

Ankaramite (from Hualālai) – a basalt with >40% mafic phenocrysts, and those phenocrysts consist of olivine and pyroxene olivine

Pyroxene crystals, weathered out of ankaramite lavas, East Maui SW rift zone

Outer, weathered surface of ankaramite from Rarotonga, Cook Islands pyroxene

Freshly broken surface of ankaramite from Rarotonga, Cook Islands olivine amygdule (former vesicle, now filled with some sort of secondary mineral) pyroxene

Vesicular basalt (from Kohala) with lots of little clusters of plagioclase feldspar phenocrysts (and a few olivine phenocrysts). plagioclase feldspar vesicle (frozen bubble) olivine

Very fine-grained (almost glassy) basalt, from Wai‘anae

pyroxene Gabbro (from Wailau, Moloka‘i) plagioclase feldspar

quartz Granite (from Mojave desert, California) plagioclase feldspar biotite, or maybe hornblende potassium feldspar

Obsidian, from near Mono Lake, California

Pumice from Pu‘u Wa‘awa‘a, Hualālai

Calcareous sandstone (from near Ko Olina, O‘ahu)

Fragment of pāhoehoe lava showing the rapidly-chilled (and therefore glassy) outer surface, and the more slowly-cooled (and therefore crystalline) interior