Sharp lemony-yellow crystals to 5 mm of the rare species milarite - from the only locale which really produces anything of beauty in North America, with the exception of a few grayish pieces from the East Coast's old mines. And these are not available either...I gather they came out in the 60s and 70s. Few turn up today for sale. The milarites are embedded within and sticking out from matrix of crystallized feldspar var. adularia: referred to as "valencianite" by many because of the unusual luster and form of the crystals compared to feldspar from other Mexican locales.