feldsparnoun [ C or U ]uk /ˈfeld.spɑːr/ us /ˈfeld.spɑːr/ specialized
Examples from literature
- It contains a large proportion of mica, a small proportion of quartz and still less feldspar, but generally an abundance of iron pyrites in very minute crystals, which, on exposure, are decomposed.
- It is the metallic base of mica, feldspar, slate, and clay.
- It was made of black, glassy lava mixed with bits of feldspar.
- The purest clay found in nature is porcelain clay, or kaolin, which results from the decomposition of a rock composed of feldspar and quartz, and it is almost always mixed with quartz.
- What little feldspar there was is reduced to quartz and mica, and the quartz pebbles are drawn out into lenses.