THE MINERAL STILBITE


Stilbite is a common and perhaps the most popular zeolite mineral for collectors. Stilbite crystals can aggregate together to form a structure resembling wheat sheafs. This hourglass structure looks like several crystals stacked parallel to each other with the tops and bottoms of this structure fanning out while the middle remains thin. Stilbite's hallmark crystal habit is unique to stilbite and a rarer but related zeolite called stellerite. Whether in the wheat sheafs or not, stilbite can be a hansome specimen with its pearly luster and often colorful pink tints. Stilbite commonly forms nice crystals inside the petrified bubbles (called vesicles) of volcanic rocks that have undergone a small amount of metamorphism.

Stilbite's structure has a typical zeolite openness about it that allows large ions and molecules to reside and actually move around inside the overall framework. The structure contains open channels that allow water and large ions to travel into and out of the crystal structure. The size of these channels controls the size of the molecules or ions and therefore a zeolite like stilbite can act as a chemical sieve. Stilbite's structure contains rings of alumino-silicate tetrahedrons oriented in one direction and this produces the prominant pinacoid faces, the perfect cleavage and the unique luster on those faces.

PHYSICAL CHARACTERISTICS:

  • Color is pink or white; also tinted yellow and red.
  • Luster is vitreous to pearly especially on the prominant pinacoid and cleavage surfaces.
  • Transparency: crystals are transparent to mostly translucent.
  • Crystal System is monoclinic; 2/m
  • Crystal Habits include platy often thin crystals that can aggregate together into a wheat sheaflike structure. The prominant pinacoid is sometimes but rarely modified by other pinacoid and prism faces. Cruciform (cross-like) twins can also be found. Also forms radiating nodules.
  • Cleavage is perfect in one direction parallel to the prominant pinacoid.
  • Fracture is uneven.
  • Hardness is 3.5 - 4.
  • Specific Gravity is approximately 2.2 (very light)
  • Streak is white.
  • Associated Minerals are quartz, calcite, babingtonite, apophyllite, heulandite, natrolite and other zeolites.
  • Notable Occurrences include Poona, India; Scotland; Iceland; New Jersey and Nova Scotia, Canada.
  • Best Field Indicators are crystal habit, luster, density and associations.
This Site Awarded
Available STILBITE specimens:
STILBITE specimen STL-26
$ 25.00 -50% = $ 12.50
Dims: 3.36x2.59x0.94in (8.53x6.59x2.39cm) .... Wt: 3.8oz (107g) .... Loc: Jalgaon, Maharashtra, India
This is a nice example of stilbite, having good color and showing three different habits in one specimen. There is a tabby crystal with somewhat concave faces, a sheaf of curved crystals, and a radial cluster, all of which present nicely against the dark host rock.
no photo
STL-26
$ 12.50
no photo
STILBITE specimen STL-27
$ 33.00 -50% = $ 16.50
Dims: 3.52x2.38x1.92in (8.93x6.04x4.88cm) .... Wt: 6.6oz (188g) .... Loc: Jalgaon, Maharashtra, India
This is a nice specimen of stilbite, showing the typical very pale pinkish-brown color, pearly luster, and wheat-sheaf habit of the species. It is accompanied by many small white tabby crystals which I suspect are the closely related white mineral, stellerite. Also, on the back, is a single lustrous brown crystal of heulandite.
no photo
STL-27
$ 16.50
no photo
STILBITE specimen STL-28
$ 36.00 -50% = $ 18.00
Dims: 3.26x0.95x0.72in (8.27x2.42x1.83cm) .... Wt: 1.38oz (39.0g) .... Loc: Poona, Maharashtra, India
This is primarily four intergrown stilbite clusters, all white, slightly curved and expanded toward their tips, and largely lined up in a row. The individual crystals are clear and colorless, and together they lend the specimen a rather silky appearance.
no photo
STL-28
$ 18.00
no photo
see this List of ALL specimens including SOLD ones

 

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