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3 - 3½
Named in 1822 by Henry James Brooke in honor of Johann Heinrich "John Henry" Heuland [March 21, 1778 Beyreuth, Germany - November 16, 1856 Hastings, Sussex, England, UK], a mineral collector and mineral dealer living in England.
Note on the distinguishing differences between heulandite and clinoptilolite (

"Zeolite mineral species shall not be distinguished solely on the basis of the framework Si : Al ratio. An exception is made in the case of heulandite and clinoptilolite; heulandite is defined as the zeolite mineral series having the distinctive framework topology of heulandite and the ratio Si : Al < 4.0. Clinoptilolite is defined as the series with the same framework topology and Si : Al ≥ 4.0.

Application of the rule
Many zeolites have a widely variable Si : Al ratio, but this, in itself, is not regarded as providing adequate grounds for recognition of separate species. The exception is based on entrenched usage of the names heulandite and clinoptilolite, and their convenience for recognizing an important chemical feature. The cutoff value adopted (following Boles 1972) is arbitrary in a continuous range of compositions. The usual 50% compositional rule cannot be applied, as there are no clearly defined Si,Al end-member compositions for heulandite and clinoptilolite. Thermal stability has been used by some investigators to distinguish clinoptilolite from heulandite. This is a derivative property, however, suggested by Mumpton (1960) as an aid to identification, and it is not appropriate as the basis for definition. Alietti (1972) and Boles (1972) have shown that there is no gap in composition either in framework or extra-framework cation contents between heulandite and clinoptilolite, and that samples transitional in composition show intermediate properties in terms of thermal stability.

The cation content is highly variable. Ca-, Na-, and K-dominant compositions are known, and Sr, Ba, and Mg are in some cases substantial. TSi in the range 0.80–0.84. Minerals with the same framework topology but with TSi < 0.80, Si/Al < 4.0 are classified as heulandite, with which clinoptilolite forms a continuous series. Monoclinic, C2/m, or C2, or Cm.

The cation content is highly variable. Ca-, Na-, K-, and Sr-dominant compositions are known, and Ba and Mg are in some cases substantial. TSi in the range 0.71 to 0.80."

Classification of Heulandite


8 : Silicates

16 : Silicates Containing Aluminum and other Metals
10 : Aluminosilicates of Ca and alkalis URL:
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Physical Properties of Heulandite

Vitreous, Pearly
Hardness (Mohs):
3 - 3½
2.1 - 2.2 g/cm3 (Measured)    2.17 g/cm3 (Calculated)

Crystallographic forms of Heulandite

Crystal Atlas:
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Heulandite no.8 - Goldschmidt (1913-1926)
Heulandite no.38 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by

Edge Lines | Miller Indicies | Axes

Opaque | Translucent | Transparent

Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
X-Ray Powder Diffraction:
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Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Heulandite

Biaxial (+)
RI values:
nα = 1.476 - 1.506 nβ = 1.479 - 1.510 nγ = 1.479 - 1.517
Measured: 10° to 48°
Max Birefringence:
δ = 0.003 - 0.011
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
r > v

Relationship of Heulandite to other Species

8/.-Celsian-Hyalophane Series
16.10.4Thomsonite-CaNaCa2[Al5Si5O20] · 6H2O
16.10.5Gonnardite(Na,Ca)2(Si,Al)5O10 · 3H2O
16.10.6MesoliteNa2Ca2Si9Al6O30 · 8H2O
16.10.8Garronite-CaNa2Ca5Al12Si20O64 · 27H2O
16.10.9BoggsiteCa8Na3(Si,Al)96O192 · 70H2O
16.10.12Fedorite(Na,K)2-3(Ca4Na3)Si16O38(OH,F)2 · 3.5H2O
16.10.13WillhendersoniteKCa[Al3Si3O12] · 5H2O
16.10.14Barrerite(Na,K,Ca0.5)2[Al2Si7O18] · 7H2O
16.10.15Mordenite(Na2,Ca,K2)Al2Si10O24 · 7H2O
16.10.16Reyerite(Na,K)2Ca14(Si,Al)24O58(OH)8 · 6H2O
16.10.20GobbinsiteNa5(Si11Al5)O32 · 11H2O
16.10.23OffretiteKCaMg(Si13Al5)O36 · 15H2O
16.10.24PerlialiteK9Na(Ca,Sr)[Al2Si4O12]6 · 15H2O
16.10.27Sodium Dachiardite(Na2,Ca,K2)4-5Al8Si40O96 · 26H2O
16.10.28Mazzite-Mg(Mg,K,Ca)5(Si26Al10)O72 · 28H2O
16.10.29RoggianiteCa2Be(OH)2Al2Si4O13 · 2.5H2O

Other Names for Heulandite

Name in Other Languages:

Other Information

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Heulandite

Reference List:
Ventriglia, U. (1955): La struttura della heulandite. Periodico di Mineralogia – Roma, 49-83.

Merkle, A.B., and M. Slaughter (1968): Determination and refinement of the structure of heulandite. American Mineralogist: 53: 1120-1138.

Alberti, A. (1972): On the crystal structure of the zeolite heulandite. Tschermaks Mineralogische und Petrographische Mitteilungen: 18: 129-146.

Boles, J.R. (1972): Composition, optical properties, cell dimensions and thermal stability of some heulandite group zeolites. American Mineralogist: 57: 1463-1493.

Alberti, A. (1973): The structure type of heulandite B (heat-collapsed phase). Tschermaks Mineralogische und Petrographische Mitteilungen: 19: 173-184.

Alietti, A. (1972): Polymorphism and crystal chemistry of heulandite and clinoptilolite. Am. Min.: 57: 1448-1462.

Boles, J.R. (1972): Composition, optical properties, cell dimensions and thermal stability of some heulandite group zeolites. Am. Min.: 57: 1463-1493.

Comodi, P., G.D. Gatta, & P.F. Zanazzi (2001): High-pressure structural behavior of heulandite. European Journal of Mineralogy: 15: 247-255.

R. Murao, K. Yubuta, R. Miyawaki and K. Sugiyama (2009): Analysis of aluminoceladonite included in green heulandite. JAKOKA: 2009 Annual Meeting of the Japan Association of Mineralogical Sciences, abs. R4-11, p. 105.

Gabuda, S.P., Kozlova, S.G., Kolesnikov, A.S., Petrov, A.K. (2013): Microwave Absorption and Structure of Zeolite Water in Heulandite and Clinoptilolite by 1H NMR. Journal of Structural Chemistry, 54, S119-S125.

Internet Links for Heulandite

The following Heulandite specimens are currently listed for sale on

Localities for Heulandite

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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