The mineral name APOPHYLLITE is now a group name. It includes the minerals FLUORAPOPHYLLITE, Hydroxyapophyllite and Natroapophyllite.
A single crystal of Fluorapophylite. Note the striations on the prism faces that are parallel to the "C" axis.
A pair
of Fluorapophylite crystals from
India.
Stubby, green crystals of Fluorapophylite on a matrix of Stilbite.
Fluorapophylite with Prehnite and
Gyrolite (small white spheres) from India.
CHEMISTRY - KCa4Si8O20(F,OH).8H2O
CRYSTALLOGRAPHY - Tetragonal
CRYSTAL GROWTH AND HABITS - Crystals are typically prismatic to tabular and can be pseudo cubic in form. Prism faces are usually striated parallel to the "C" axis.
COLOR AND OTHER OPTICAL PROPERTIES - Crystals are commonly colorless and clear to milky or white, but can also be pink, and light shades of yellow or green.
HARDNESS - 4.5 - 5
SPECIFIC GRAVITY - 2.33 - 2.37
LUSTER - Vitreous with a pearly luster on pinacoidal faces.
STREAK - White
BREAKABILITY - Good cleavage in one direction, poor in another, uneven fracture and brittle.
OCCURRENCE - Fluorapophyllite is a zeolite mineral and occurs as a secondary deposit in gas pockets in basalt. It can also occur in openings in other rocks like granite or as a late stage mineral in some hydrothermal deposits.
ASSOCIATED MINERALS - Other Zeolites, Calcite, Pectolite and Quartz.
MINERAL NAME - "Fluor" for its abundance of fluorine and "apophyllite" from the Greek for its tendency to flake or exfoliate when heated.