Zircon var. Cyrtolite

Excellent specimen of well-formed brownish crystals of Zircon var. Cyrtolite from the Butterfield pegmatites, South Platte Pegmatite Mining District, Jefferson County, Colorado, USA. Measures ~75,000 CPM on my Ludlum Model 3 Counter with the 44-9 probe due to high Thorium content. Rare!