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Scolecite
Current inventory:  1 gem
 

Chemistry:  CaAl₂Si₃O₁₀·3(H₂O)

Discovered in 1813;   IMA status: Valid (pre-IMA; Grandfathered).
The name Scolecite is from the Greek word skolec for "worm" in reference to the mineral's reaction to a flame because it sometimes curls up like a worm.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/J.21-60

8 : Silicates
J : Tectosilicates (network) without anions unfamiliar to the tetraheders
21 : Zeolite group, Natrolite - Thomsonite series

Crystal Data

Crystallography:

Monoclinic - Domatic

Crystal Habit:

Crystals are slender prismatic, may be square in cross section, elongated and striated, to 30 cm. Characteristically in radiating sprays, fibrous masses; nodular, massive. Twinning: On [100], twin axis [001], common, as contact or penetration twins.

Physical Properties

Cleavage:

[110] Perfect

Fracture:

Uneven

Tenacity:

Brittle

Moh's Hardness:

5.0 - 5.5

Density:

2.16 - 2.40 (g/cm³)

Luminescence:

May fluoresce yellow to brown under SW and LW UV

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, White, Pink, Salmon, Red, Brownish, Green

Transparency:

Transparent to Subtransparent

Luster:

Vitreous, Silky

Refractive Index:

1.507 - 1.521  Biaxial ( - )

Birefringence:

0.010

Dispersion:

Relatively Strong; r < v

Pleochroism:

None

Occurances

Geological Setting:

Primarily in cavities in basalts; in gneisses and amphibolites, and in laccoliths and dikes derived from syenitic and gabbroic magmas.

Type Locality:

Kaiserstuhl in Baden

Year Discovered:

1813

View mineral photos:

Scolecite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Scolecite is a member of the Zeolite Group of minerals that includes over 40 minerals and these gem-type minerals: Analcime, Barrerite, Chabazite, Epistilbite, Gmelinite-Na, Goosecreekite, Mordenite, Natrolite, Pollucite, Scolecite, Stellerite, Stilbite, Thomsonite and Yugawaralite. Scolecite is not a rare mineral but crystals large enough for faceting are very rare and usually kept as mineral specimens by collectors. The small number of faceted gems that exist are usually small and colorless. Chatoyant cabochons are occassionally available. Scolecite is pyroelectric and piezoelectric. Current sources of Scolecite crystals are in the Poona, Nasik, and Bombay districts, Maharashtra, India; and near Bento Goncalves, Rio Grande do Sul, Brazil. Non-gem specimens can be found in the USA on the south fork of the Toutle River, Cowlitz Co., in the Pioneer quarry, Bremerton, Kitsap Co., and other localities in Washington; and on North Table Mountain, Golden, Jefferson Co., Colorado.
 

  
Scolecite gems for sale: