Sanidine
Taiji city, Higashi-Muro county, Wakayama pref., Japan
Crystal at upper left: 10 mm. Floaters of sanidine. The upper left specimen is a Carlsbad-law twin.
Recovered from a weathered part of quartz porphyry, a member of an arc-shaped dike of a caldera complex. Formed in the middle Miocene (14 Ma).
Sanidine from this location was described in 1932, and was designated the prefectural mineral of Wakayama in 2016 by the Geological Society of Japan.