GNEISS n.
ock, consisting, like granite, of quartz, feldspar, and mica, but having these materials, especially the mica, arranged in planes, so that it breaks rather easily into coarse slabs or flags. Hornblende sometimes takes the place of the mica, and it is then called hornblendic or syenitic gneiss. Similar varieties of rela…
GONIOMETER n.
An instrument for measuring angles, especially the angles of crystals, or the inclination of planes. Contact, or Hand, goniometer, a goniometer having two movable arms (ab, cd), between which (at ab) the faces of the crystals are placed. These arms turn about a fixed point, which is the center of the graduated circle o…