|CroninProjects.org/ Vince/ PhysGeoLab/ igrox.index.html|
Basalt with columnar jointing along the Deschutes River in central Oregon. Photo by Vince Cronin.
Click on the underlined links in the tables below to obtain more information about the igneous rock, texture or mineral, including some specimen pictures.
|aphanitic: very fine grained|
|glassy: texture of broken glass|
|phaneritic: mineral grains are coarse/large enough to be distinct|
|porphyritic: larger grains in a finer-grained matrix or ground mass|
|pyroclastic: "fire broken" or blasted from a volcano|
|scoriaceous: low-density rock with very large number of small gas-bubble voids|
|vesicular: with gas-bubble voids frozen in rock at time of crystallization|
|alkalai feldspar||biotite||plagioclase feldspar||quartz|
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