A Geoscience Digital Image Library

DescriptionApophyllite, KCa4Si8O20(F,OH)8·H2O, is the official name for three white to grayish tetragonal minerals with a pearly to vitreous luster, having a specific gravity of 2.3 to 2.4 and a hardness of 4.5 to 5 on the Mohs scale. These minerals are fluorapophyllite, hydroxyapophyllite, and natroapophyllite. Fluorapophyllite is by far the most abundant and colorful of the three and is usually what is referred to when a specimen is just labeled apophyllite. Apophyllite occurs with zeolites in amygdules in basalts and other igneous rocks. Apophyllite is also found in the voids in the contact metamorphic zone limestones that surround intrusive rocks. This sample contains large euhedral apophyllite (left end) in a sea of smaller apophyllite crystals. It is about 12 cm across. Apophyllite is named from the Greek apophylliso meaning “it flakes off”.
LocationAustralia. Near Tyrol.
PhotographerNessa Eull. 2002-02-07.
CollectionUniversity of North Dakota Mineralogy Collection #1508.
Key wordsapophyllite, australia, fluorapophyllite, hydroxyapophyllite, natroapophyllite
Tech details359 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60 mm AF Nikon micro lens.
GeoDIL number2259