Zeolite is a general term for hydrous alkali or alkaline earth metal aluminosilicate minerals—the water content changes in different environments. There are 40 kinds of natural zeolite and 150 kinds of artificial zeolite.
The color is generally light gray, but also yellow, green, brown, red and other colors.
Zeolites have the properties of adsorption, ion exchange, catalysis, acid resistance and heat resistance. It is widely used as adsorbent, ion exchanger and catalyst.
More than 1000 zeolite deposits have been found in the world, which are concentrated in the Pacific and Mediterranean regions.
Zeolite comes from the Greek words Zein (boiling) and Lithos (stone) because when the blowpipe flame burns, most zeolites expand and bubble as if boiling.
Basic properties of zeolite
Composition: Hydrous aluminosilicates of sodium and calcium.
Shape: the crystals are plate, column and fiber, and the aggregates are radial and bundle. Most have complete cleavage.
Optical property: colorless and transparent in thin film. Negative low protrusion. The interference color is mostly Grade I gray.
Occurrence: mostly feldspar and feldspar-like alteration products or late gas liquid fillings in pores, crystal cavities and fractures.
Zeolite type
Natrolite
The name of Natrolite comes from the Latin word Nitrum (Greek word Nitron, meaning sodium) and the Greek word Lithos (stone), and its chemical composition is Na2 [Al2Si3O10] ・ 2H2O.
It belongs to orthorhombic system. The crystals are long columnar and fibrous, and the aggregates are radial. With {110} complete cleavage. Np=1.473~1.480，Nm=1.476~1.482,Ng=1.485~1.493,Ng-Np=0.012～0.013。
The interference color is Grade I yellow. Parallel extinction or symmetric extinction. Positive ductility. Two axis (+), 2V=58 °.
Natrolite crystals are columnar, and some crystals are transparent but rare; The aggregates are radial, fibrous or spherical.
Natrolite is colorless, white, or with light yellow, light green, light red, or glass luster. It is commonly found in the amygdala or cavity of basalt and other extrusive rocks;
Some are formed by replacing nepheline or sodalite in nepheline syenite and phonolite; Some are formed by replacing plagioclase in dolerite and felsic rock.
The yellow shiny dense Natrolite block produced in Germany is bright in color, and some can show a circular pattern after polishing. The contact zone between Canadian nepheline syenite and limestone produces transparent Natrolite
crystals.
There are excellent Natrolite crystals in basalt from Anhui and Jiangsu provinces in China. Alkaline pegmatite in Xinjiang produces Natrolite, which coexists with calcite.
Chabazite
The name of Chabazite is derived from the Greek word Chabazios or Chalazios. The composition is (Ca, Na2) [AISi2O8] 2 ・ 6H2O.
It belongs to the trigonal crystal system and is a complex rhombohedral crystal shape close to a cube. It has rhombohedral cleavage. No=1.480~1.485，Ne=1.478~1.490,INe-Nol=0.002～0.005。
The interference color is Grade I gray. It is parallel extinction or symmetric extinction. One axis (ten) or (one), but usually two axis crystallization.
Heulandite
Heulandite is named after the British mineral collector Heuland, and the crystal form of this mineral is usually plate and sheet. The composition is (Ca, Na2) [Al2Si7O18] ・ 6H2O.
It belongs to monoclinic system. The crystals are in the form of plates and sheets. {010} cleavage is complete. Np=1.496～1.498Nm=1.497~1.499,Ng=1.501~1.505,Ng-Np=0.005～0.007。 Ng//b,Np)c=68°～84°。 Two axis (+), 2V=0 °~55 °.
Stilbite
The name of Stilbite originates from the Greek word Stilbein (reflection and luster), which emphasizes that minerals have pearl light translation and glass luster; the chemical composition is (Na2, Ca) [Al2SiO18] · 7HO.
It belongs to monoclinic system. The crystals are thin, flaky and fibrous, and the aggregates are radial and fascicular. {010} cleavage is complete. Np=1.482~1.497,Nm=1.491~1.499,Ng=1.493～1.502，Ng-Np=0.011~0.005。 Nm//b,NpAc=3°～12°。 Double crystal and cross twin are commonly interspersed. Two axis (I), 2V=30 °~49 °.
Mesolite
The name of Mesolite comes from the Greek words Mesos (middle, medium) and Lithos (stone), emphasizing that its chemical composition is between Natrolite and Scolecite.
The composition is Na2Ca2 [Al2Si3O10] ・ 8H2O.
It belongs to monoclinic system. The crystals are needle-like and fibrous. Cylindrical cleavage is complete. N=1.504，Nm=1.505,Ng=1.506，Ng-Np=0.002。 Nm//b,Np∧c=8°。 Double crystals are visible. Two axis (+), 2V=80 °.
Laumontite
Laumonte is named after Laumonte. The composition is Ca [Al2Si2O8] ・ 4H2O.
It belongs to monoclinic system. The crystals are columnar and acicular, and the aggregates are radial. {010} {110} cleavage is complete. Np=1.504～1.513,Nm=1.514~1.524,Ng=1.516～1.525，Ng-Np=0.012.Nm//b,Ng∧c=28°～40°。
The highest dry color is Grade I yellow. Oblique extinction. Positive ductility. Double crystals are visible. Two axis (I), 2V=32 °~47 °.
Scolecite
The name of “Scolecite” originates from the Greek word Skolex (acarid) because when the blowpipe flame burns it, it forms a coiled insect-like substance.
The composition is Ca [Al2S3iO10] ・ 3H2O. It belongs to monoclinic system. The crystals are columnar, rod-shaped and needle-shaped, and the aggregates are radial and spherical. {110} cleavage is complete. Np=1.509~1.514,Nm=1.516~1.520,Ng=1.521~1.525，Ng-Np=0.011~0.012。 Ng//b，NpAc=15°～18°。 Two axis (I), 2V=36 °~58 °.
The crystal of Scolecite is columnar, and the aggregate is needle, radial or fibrous. Colorless or white, some pink and yellow. Glass luster, silk luster in the case of fiber.
It is commonly found in the cavities of basic volcanic rocks, some in the metamorphic rocks of calcareous rocks, and some in hydrothermal minerals.
Mordenite
Mordenite is named after the town of Morde in Kings New Kosher, Canada.
The composition is Na2Ca2 [AISi5O12] 4 ・ 12H2O. The rhombic crystal system has long columnar, acicular, filiform and hairlike crystals, and the aggregates are like brocade and radiation.
Negative high negative low protrusion. Np=1.472~1.483,Nm=1.475~1.485，Ng=1.477～1.487,Ng-Np=0.004～0,005。
The highest dry color is Level I dark gray. Parallel extinction. Negative ductility. 2V=60 °~90 °.
Phillipsite
Phillipsite is named after the British mineralogist Phillips. The composition is (K2, Na2, Ca) [AIS3iO8] 2 ・ 6H2O. Monocline system, single columnar crystals are rare, often in the form of fibrous, globular and radial aggregates.
Colorless in the flakes. Negative low protrusion. Np=1.483～1.504,Nm=1.484~1.509,Ng=1.486~1.514，Ng-Np=0.003～0.010。 The highest dry color is Grade I dark gray – Grade I gray white. Oblique extinction, Ng λ c=11~13 °. Positive ductility. See cross interpenetrating twin. Two axis (+), 2V=60 °~80 °.
Analcime
Analcime belongs to the analcime family. The chemical composition of analcime is NaAlSi2O6.H2O.
Crystals often appear as tetragonal trioctahedron or cubes. It is white, gray, yellow, green, pink or colorless. Glass luster, transparency, hardness of 5~5.5, density of 2.24~2.29g/cm. Refractive index N=1.479~1.493. It is usually colorless or white-faceted gems, weighing 1-2 carats.
Analcime has a relatively wide range of mineralization temperatures. Analcime is generally believed to be a high-temperature mineral with an upper limit temperature of 525 ℃.
The analcime formed in the late stage of some neutral and basic igneous rocks is a primary mineral, which is often associated with Prehnite and other zeolites in bubbles.
In the plutonic rocks, analcime occurs in the dolerite as a primary mineral or a secondary mineral of nepheline;
Zeolite coexists with nepheline in some alkaline rocks. In the hypabyssal rocks, analcime is found in some olivine dolerites, sometimes enriched to form analcime dolerites or olivine dolerites.
In altered tuffs, analcime can be formed by alteration of albite or orthoclase in sodium-rich solution.
Analcime is also formed in the hydrothermal stage, which is found in the bubbles of igneous rocks, and coexists with Prehnite, Chabazite, Thomsonite, and Stilbite.
Large white crystals of analcime are produced in Canada; Basalt lavas in many countries, such as the United States, produce analcime. Analcime has been found in alkaline pegmatites in Xinjiang, China.
Thomsonite
The Thomsonite belongs to the hydrocalcimite family. The chemical composition of Thomsonite is NaCa2 [Al2Si2O8] 2.5 ・ 6H2O.
The crystals are columnar, and there are few complete crystals, which are generally columnar or radial aggregates.
Some radial crystals have concentric bands or spots of different colors. Thomsonite is colorless, white, pink and yellow. Glass luster, pearl luster on cleavage surface, transparent to translucent. Hardness: 5 ～ 5.5, density: 2.1 ～ 2.4g/cm; Refractive index N=1.518~1.544, Nm=1.513~1.533, N=1.497~1.530; Birefringence NN=0.006~0.015.
Thomsonite is a secondary mineral, which often occurs in amygdaloid and cavity fillings of basic volcanic rocks, with few crystals.
It is ubiquitous in basalt and coexists with siderite and other zeolites. In some alkaline rocks (such as nepheline syenite), Thomsonite can associate with nepheline, feldspar and anorthite. High-quality Thomsonite is produced in the United States; Translucent green zeolite is produced in Michigan, USA.
Healing properties of zeolite
Zeolite is the generic name of a group of crystals commonly found on parent rocks, including apophyllite, wollastonite, sodalite, Prehnite, and distillate stone. This beautiful symbiotic stone has decorative effect and can beautify the environment.
In addition, it can absorb toxins and odors. It is said that burying it underground or placing it near gardening is beneficial to agriculture and gardening.
Zeolite is a good helper of finger pressure therapy. It is said that it can help people adapt to energy and enhance the therapeutic effect. Zeolite can be used to eliminate swelling (especially goiter) and toxins in the body.
Conclusion:
Zeolite minerals are alkaline or alkaline earth metal aluminosilicates containing water (also called “zeolite water”). There are more than 30 kinds of zeolite minerals, some of which can be used as gemstones, such as analcime, rodite, sodium zeolite, mesozeolite, calcium zeolite, etc.
Under the action of internal force, zeolite minerals are formed in the low-temperature hydrothermal stage, coexisting with calcite, pith, quartz, etc. Zeolites are commonly found in fissures or amygdaloids of magmatic rocks (mainly basic volcanic rocks), some in hydrothermal veins and hot spring sediments, and some are products of metasomatic silicate minerals such as feldspar and nepheline.
Endogenous zeolite is widely distributed with large crystals, which can form gemstones.
Zeolite minerals are mainly formed in pyroclastic sedimentary rocks under external forces. Sedimentary zeolites are mostly siliceous volcanic glass and other volcanic debris formed by aluminosilicate materials, which react with interstitial water and form zeolite minerals under diagenesis in alkaline environment.
The zeolite crystals in the sedimentary rocks are fine, and the zeolite tuffs are white or light gray; some are red, green or yellow, which may form jade.