Natrolite
Discovered
in 1803 ; IMA
status:
Valid (pre-IMA; Grandfathered)
Chemistry
Chemical
Formula :
Na 2 Al 2 Si 3 O 10
• 2H 2 O
Hydrated Sodium Aluminum Silicate
Molecular
Weight:
380.22 gm
Composition:
Sodium
12.09 %
Na
16.30 %
Na2 O
Aluminum
14.19 %
Al
26.82 %
Al2 O3
Silicon
22.16 %
Si
47.41 %
SiO2
Hydrogen
1.06 %
H
9.48 %
H2 O
Oxygen
50.49 %
O
100.00 %
100.00 %
= TOTAL OXIDE
Classification
Mineral
Classification :
Silicates
(Germanates)
Strunz 8th
Ed. ID :
8/J.21-10
Nickel-Strunz 10th
Ed. ID :
9.GA.05
9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H 2 O; zeolite family
A : Zeolites with T 5 O 10 Units – The Fibrous Zeolites
Related
to:
Zeolite
Group. Natrolite Subgroup. Dimoroh of Gonnardite.
Members
of Group:
Zeolite Group:
Amicite, Barrerite, Bellbergite, Bikitaite, Boggsite,
Brewsterite, Chabazite, Chabazite-Lévyne Subgroup, Clinoptilolite,
Cowlesite, Dachiardite-Na, Epistilbite, Erionite, Faujasite
Subgroup, Ferrierite, Garronite, Gismondine, Gmelinite,
Gobbinsite, Goosecreekite, Harmotome, Heulandite, Laumontite,
Lévyne, Mazzite, Merlinoite, Montesommaite, Mordenite,
Offretite, Paulingite, Pollucite, Stellerite, Stilbite,
Thomsonite, Tschernichite, Wairakite, Willhendersonite,
Yugawaralite
Members
of Subgroup:
Natrolite
Subgroup:
Gonnardite, Mesolite, Natrolite, Paranatrolite, Scolecite
Varieties:
Bergmannite,
Galactite, Germanate-natrolite, Kondrikovite, Mooraboolite,
Spreustein
Synonyms:
Ædelite (of Kirwan),
Aedelite, Apoanalcite, Bergmannite, Crocalite, Crockalite, Epinatrolite,
Fargite, Feather Zeolite, Galactite, Lehuntite, Mealy
Zeolite, Mesotype, Natronite (of ?), Needlestone,
Portite
Crystal
Data
Crystallography :
Orthorhombic
- Pyramidal
Crystal
Habit :
Crystals
short to long prismatic, to 1 m, striated. In stellate
or interlacing groups; also radiating fibrous, granular,
or compact, massive.
Twinning :
On
{110}, {011}, {031}
Physical
Properties
Cleavage :
Perfect
on {110}, parting on {010}
Fracture :
Irregular/uneven
Tenacity :
Brittle
Moh's
Hardness :
5.5
- 6.0; Vickers: VHN200=1239 - 1467 kg/mm 2
Density :
2.20 - 2.26 (g/cm3 )
Luminescence :
Fluorescent; SW UV
= yellow-orange, pale green, LW UV = yellow-orange,
greenish white
Radioactivity :
Not
Radioactive
Other:
Piezoelectric
and Pyroelectric
Optical
Properties
Color :
Colorless,
white, gray, bluish, pink, yellowish white
Transparency :
Transparent
to translucent
Luster :
Vitreous
to pearly, silky
Refractive
Index :
1.473 - 1.496 Biaxial ( +
)
Birefringence :
0.0120
- 0.0130
Dispersion :
Weak, r < v
(0.005)
Pleochroism :
Weak;
X = colorless, Y = colorless, Z = colorless
Occurances
Geological
Setting:
In
cavities in amygdaloidal basalts and related igneous
rocks, one of the last minerals to form; fills seams
in granite, gneiss, and syenite.
Common
Associations:
Zeolites,
Calcite, Nepheline, Sodalite, Quartz
Common
Impurities:
Ca,
K
Type
Locality:
Hohentwiel, Singen, Hegau, Baden-Württemberg,
Germany
Year
Discovered:
1803
View
mineral photos:
Natrolite
Mineral Photos and Locations
Unusual
Gem Categories
Fluorescent
Gems ,
Piezoelectric
Gems ,
Pyroelectric
Gems
More
Information
Mindat.org
Webmineral.com
Natrolite
is one of the more popular and well known members 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 .
Natrolite
usually forms as elongated
crystals so faceted gems are often cut as elongated
emerald cut gems. Natrolite gems are colorless and have
weak dispersion and might be considered somewhat uninteresting
except for the fact that Natrolite is both piezoelectric
and pyroelectric
and commonly exhibits yellow to orange or pale green fluorescence
under both shortwave and longwave UV light.
Natrolite was
discovered in 1803 at Hohentwiel, Singen, Hegau, Baden-Württemberg,
Germany. Hohentwiel is an extinct volcano. Natrolite was named by German chemist Martin Heinrich Klaproth
(1743-1817) from
the Latin word natron meaning soda , for
its sodium content, and the Greek word λίθος , (lithos ) meaning stone.
Crystals
can be found in many locations worldwide but gem quality
crystals are relatively rare. Notable occurances are
the Höwenegg
quarry, Hegau, Baden-Württemberg, Germany (the Type
Locality); Puy de Marman, near Veyre, Puy-de-Dôme,
France. In the Dean quarry, St. Keverne, Lizard Peninsula,
Cornwall, England; White Head, County Antrim, Ireland;
Langesundsfjord and Tvedalen areas, Norway; Khibiny
and Lovozero massifs, Kola Peninsula, Russia (large
crystals); in the USA, at Bound
Brook, Somerset County, New Jersey; from north of Livingstone,
Park County, Montana; around Springfield, Lane County, Oregon;
and at the Gem mine, San Benito County, California, USA.
In Canada, huge crystals from the Johnston asbestos
mine, near Thetford, and from Mont Saint-Hilaire, Quebec;
in the Bay of Fundy district, Nova Scotia; and along
the Ice River, British Columbia.
Natrolite
gems for sale:
please click on picture
Gem:
Natrolite
Stock
#:
NATRO-001
Weight:
5.7730
ct
Size:
17.22
x 10.60 x 6.71 mm
Shape:
Cushion
w/ Checkerboard table
Color:
Colorless
Clarity:
Eye
Clean
Origin:
Bound
Brook, New Jersey, USA
Treatment:
None
(natural)
Price:
$430.00
RESERVED [
Make an offer ]
Pictures
are of the actual gem offered for
sale. Gem images are magnified to
show detail.
please click on picture
Please
click on the pictures above for a larger view.
A
very, very large, bright and beautiful
Natrolite from Bound Brook, New Jersey that
is eye clean! A true rarity at this
size and clarity!
Gem:
Natrolite
Stock
#:
NATRO-002
Weight:
0.7955
ct
Size:
5.56
x 5.47 x 4.22 mm
Shape:
Princess
Color:
Colorless
Clarity:
Eye
Clean - SI2
Origin:
Bound
Brook, New Jersey, USA
Treatment:
None
(natural)
Price:
SOLD
(but we have others)
Pictures
are of the actual gem offered for
sale. Gem images are magnified to
show detail.
A
very rare gem from an unusual US location
that is beautifully faceted.