The all-time classic locality for this mineral is the Monteponi Mine, Iglesias, on the Island of Sardinia, Italy. This locality has produced large crystals with excellent form.
Two African localities have also produced good specimens, namely the Touissit Mine in Morocco and the Tsumeb Mine in Tsumeb, Namibia. Small crystals have come from Matlock, Derbyshire, England; Tarnowitz, Poland; Dundas, Tasmania, and Broken Hill, New South Wales, Australia. Phosgenite also occurs as an alter
ation product of the lead slag
s at Lavrion Greece.
Phosgenite has been found only sparingly in the U.S., particularly at the Mammoth-Saint Anthony Mine, Tiger, Pinal Co., Arizona; the Terrible Mine in Custer Co., Colorado; the Stephenson-Bennet Mine in Dona Ana Co., New Mexico; and the Silver Sprout Mine in Inyo Co., California.