CHEMISTRY - CaAl2Si3O10.3H2O
CRYSTALLOGRAPHY - Monoclinic, pseudotetragonal
CRYSTAL GROWTH AND HABITS - Scolecite crystals are normally slender and prismatic. They may be striated parallel to the long axis of the crystal and they may also be square in cross section. Their growth habit is as radiating clusters or sprays; they may also be nodular or fibrous to massive. Twinning in Scolecite is common along {100} as penetration or contact twins.
COLOR AND OPTICAL PROPERTIES - Scolecite is most commonly colorless to white and is transparent to translucent.
HARDNESS - 5 - 5.5
SPECIFIC GRAVITY - 2.25 - 2.29
LUSTER - Vitreous to silky when fibrous
STREAK - White
BREAKABILITY - Very brittle with cleavge along {110} and {110} and an uneven fracture.
OCCURRENCE - Scolecite occurs primarily in cavities in basalt. It also occurs in amphibolites and in high grade metamorphics like gneisses.
ASSOCIATED MINERALS - Zeolites, Prehnite, Calcite
MINERAL NAME - From the Greek for worm in allusion to the curling of the crystals when heated.