CHEMISTRY - NaAl3(SO4)2(OH)6
CRYSTALLOGRAPHY - Hexagonal
CRYSTAL GROWTH AND HABITS - Rarely forms crystals - tabular or rhombohedral, often pseudo cubic. It is most commonly massive to granular.
COLOR AND OPTICAL PROPERTIES - Commonly white but also grayish, yellowish or brownish, sometimes reddish brown; translucent to sub transparent;
HARDNESS - 3.5 - 4
SPECIFIC GRAVITY - 2.6 - 2.9
LUSTER - Vitreous to somewhat pearly to dull
STREAK - White
BREAKABILITY - Good cleavage {0001} for crystals and uneven to splintery fracture for the massive variety. Brittle
OCCURRENCE - Natroalunite is relatively rare. It is found in the Sugarloaf Mountains near Quartzite, AZ and in the Funeral Mountains in Death Valley, California.
ASSOCIATED MINERALS - Quartz, Kaolin, Diaspore
MINERAL NAME - Named because it is the sodium rich member of the Alunite series.