A large, pristine and lustrous 7 mm dark blue cube of pseudoboleite coating boleite from Santa Rosalia, Boleo, Mexico. The 1 mm thick pseudoboleite epitaxially overgrew the 6 mm boleite cube. The crystal edges have the typical reverse step found in this rare mineral combination. Old dealer stock of Dr. Gary Hansen and not shown since the early 1980s! 0.7 x 0.7 x 0.7 cm