Photomicrograph of rock thin section: Gabbroic inclusion
Photomicrograph of gabbroic inclusion in Ogres Brow basaltic andesite. A rock thin section is created by gluing a small piece of rock onto a glass slide, then grinding it down to a thickness of 30 microns (the average human hair is about 100 microns in diameter) so that light shines through it when examined under the microscope. In this image, euhedral reddish-brown amphibole surrounds relict pyroxene, olivine, and plagioclase crystals. Interstices are filled with vesiculated quenched basalt. Field of view is 20 x 13 mm. Sample 09KCnye107 from Kasatochi Volcano in Alaska.