These stones and rough material are extremely hard to find.
Specimen grade hyalite comes from many places. ONLY in the state of Utah, USA is gem quality adularescent material found in veins/seams thick enough to cut gemstones! The small deposits in Utah are depleted of cutting quality! Satin flash opal is indeed very hard to find!
Hyalite opal was formed by hot spring geyser deposits and does not have colorplay like other opal, instead the light rolls off the internal bubble structure and flashes back at the onlooker. Rarely does Satin Flash display colors and if it does, it's not the same as precious opal.