Analcime
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Analcime is named from the Greek word analkis for weak, alluding to the weak electrostatic charge developed when rubbed or heated. Analcime is weakly piezoelectric.

Discovered in 1801;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

NaAl(Si₂O₆)·(H₂O)

Hydrated Sodium Aluminum Silicate

Molecular Weight:

220.15 gm

Composition:

Sodium

10.44 %

Na

14.08 %

Na₂O

Aluminum

12.26 %

Al

23.16 %

Al₂O₃

Silicon

25.51 %

Si

54.58 %

SiO₂

Hydrogen

0.92 %

H

8.18 %

H₂O

Oxygen

50.87 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/J.27-10

Nickel-Strunz 10th Ed. ID:

9.GB.05

9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H₂O; zeolite family
B : Chains of single connected 4-membered rings

Related to:

Zeolite Group. Analcime-Pollucite Series and the Analcime-Wairakite Series. The sodium analogue of Pollucite.

Members of Group:

Zeolite Group: Alflarsenite, Amicite, Ammonioleucite, Analcime, Barrerite, Beaumontite (of Lévy), Bellbergite, Bikitaite, Boggsite, Brewsterite, Chabazite, Chabazite-Lévyne Subgroup, Chiavennite, Clinoptilolite, Cowlesite, Dachiardite, Direnzoite, Edingtonite, Epistilbite, Erionite, Faujasite Subgroup, Ferrierite, Ferrochiavennite, Flörkeite, Garronite, Gaultite, Gismondine, Gmelinite, Gobbinsite, Gonnardite, Goosecreekite, Gottardite, Harmotome, Heulandite, Hsianghualite, Kirchhoffite, Laumontite, Leucite, Lévyne, Lovdarite, Maricopaite, Mazzite, Merlinoite, Montesommaite, Mordenite, Mutinaite, Nabesite, Natrolite, Offretite, Pahasapaite, Paranatrolite, Parthéite, Paulingite, Perlialite, Phillipsite, Pollucite, Roggianite, Scolecite, Stellerite, Stilbite, Strontiohurlbutite, Terranovaite, Thomsonite, Tschernichite, Tschörtnerite, Wairakite, Weinebeneite, Wenkite, Willhendersonite, Yugawaralite

Varieties:

Cesian Analcime, Germanate-Analcime

Synonyms:

Analcidite, Analcine, Analcite, Cubicite, Cubizite, Cuboite, Eudnophite, Euthalite, Euthallite, Five Islands Garnet

Crystal Data

Crystallography:

Tetragonal - Dipyramidal

Crystal Habit:

Commonly euhedral, pseudocubic crystals, to 9 cm, typically showing fine twin striae. As disseminated grains; rarely granular, massive.

Twinning:

Common and repeated on [110], [101], and other orientations, from two complex displacive phase transformations during cooling

Physical Properties

Cleavage:

Very poor on {100}; Indistinct

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

5.0 - 5.5

Density:

2.24 - 2.29 (g/cm³)

Luminescence:

Fluorescent; green blue white under SW UV,green, creamy white yellow under LW UV

Radioactivity:

Not Radioactive

Other:

Weakly Piezoelectric, weakly electrostatic when rubbed or heated.

Optical Properties

Color:

Colorless, White, Gray, Yellowish, Pink, Greenish

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.479 - 1.493  Isotropic; anomalously biaxial ( + )

Birefringence:

0.0010

Dispersion:

Weak

Pleochroism:

None

Occurances

Geological Setting:

In the groundmass or vesicles of silica-poor intermediate and ma¯c igneous rocks, typically basalts and phonolites, from late-stage hydrothermal solutions, or disseminated due to deuteric alteration. In lake beds, altered from pyroclastics or clays, or as a primary precipitate; authigenic in sandstones and siltstones.

Common Associations:

Zeolites, Prehnite, Calcite, Quartz, Glauconite

Common Impurities:

None

Type Locality:

Cyclopean Islands, Aci Trezza (Acitrezza), Etna Volcanic Complex, Catania Province, Sicily, Italy

Year Discovered:

1801

View mineral photos:

Analcime Mineral Photos and Locations

Unusual Gem Categories

Piezoelectric Gems

More Information

Mindat.org
Webmineral.com

Analcime is a member of the Zeolite Group of minerals that is comprised of over 40 minerals including these gem-type minerals: Analcime, Barrerite, Chabazite, Epistilbite, Gmelinite-Na, Goosecreekite, Mordenite, Natrolite, Pollucite, Scolecite, Stellerite, Stilbite, Thomsonite and Yugawaralite. The mineral is not rare, but gem grade crystals are seldom found and are always small. Crystals are usually opaque to slightly translucent and found as colorless, white, gray, yellowish, pink and greenish. Large crystals from Mt. Ste. Hilaire, Quebec, Canada have been found that are mostly opaque white but with small facetable areas.

Analcime is one of the unusual minerals that exhibit the piezoelectric effect. Piezoelectricity is the ability of some mineral crystals to generate a voltage in response to applied mechanical stress such as an external pressure. Piezoelectricity was discovered in 1880 by French physicists, brothers Jacques and Pierre Curie.

Some localities for outstanding specimens: in Italy, at Aci Castello, Cyclopean Islands, and from Val di Fassa and Alpe di Siusi, Trentino-Alto Aldige. Large crystals from Kotchechovmo, Krasnoyarski Territory, Russia. At Breidhdalsheidhi, Iceland. In the Dean quarry, St. Keverne, Lizard Peninsula, Cornwall, England. Around Glasgow, Dumbartonshire, Scotland. In the USA, from the Lake Superior district, Houghton County, Michigan; at Cornwall, Lebanon County, Pennsylvania; from Bergen Hill, Hudson County, and West Paterson, Passaic County, New Jersey; on Table Mountain, Jefferson County, Colorado; in the Price Creek quarry, Benton County, Oregon. From the Bay of Fundy district, Nova Scotia; large crystals from Mont Saint-Hilaire, Quebec, Canada. From Flinders, Victoria, Australia.

Analcime gems for sale: