Yanacodo in Yauricocha parish, about 30 km W of Huancavelica city.
forms veins in a decomposed volcanic rock. It also fills cavities in volcanic rocks.Cavities in the chalcedony
are sometimes filled by younger colourless quartz
crystals, the youngest phase is yellow calcite
, sometimes in rough crystals. The best rough chalcedony
yields attractive polished cabochons.
is found together with blue chalcedony
, where it rarely forms irregular stalactites up to several cm long in volcanic rocks. Good Peruvian agate
, 5.7 cm wide with bands of light orange, beige, and red-brown colours. Density 2.61, hardness 7, RI 1.540 - 1.543.
J.Hyrsl (2012) Gemstones of Peru, p. 40