zeolite formation and deposits

19

Natural Zeolites Handbook, 2011, 19-36

CHAPTER 2.1 ZEOLITE FORMATION AND DEPOSITS Ioannis Marantos1*, George E. Christidis2 and Mihaela Ulmanu3 1

Institute of Geology and Mineral Exploration, Olympic Village, 136 77 Athens, Greece, E-mail: [email protected], [email protected] 2 Department of Mineral Resources, Technical University of Crete (TUC), Engineering 73100 Chania, Greece, E-mail: [email protected] 3 National R&D Institute for Non-Ferrous and Rare Metals, IMNR, Bd. Biruintei 102, 77145 Pantelimon, Romania Abstract: Zeolites are main mineral components in volcaniclastic rocks ranging in age and composition. They form by alteration mainly of volcanic glass in various geological environments, and variable chemical temperature conditions. Proposed genetical models of zeolite deposits include, wathering, diagenesis in open or closed hydrologic systems, low temperature hydrothermal systems, primary magmatic environment and impact craters. The most common zeolite species which may occur in mineable deposits are clinoptilolite-heulandite, mordenite, chabazite, analcime, and phillipsite. Mineable zeolite deposits are widespread in many countries all over the world. The world annual production of natural zeolites remains generally constant over the last 10 years and is estimated to ca 3 million tons. Although there are large high grade zeolite deposits, and there also several studies suggesting the efficiency of the zeolite material in many applications, most of the annual zeolite production is consumed in massive low value applications like pozzolanic cement and lightweight aggregates.

INTRODUCTION The name zeolite was first used by Cronsted [1] in 1756 to describe crystals of a mineral from the Svappari copper mine in Sweden, which was “boiling” during heating. Later Murray and Renard [2], recognized zeolite minerals in deep sea sediments and more recently mineralogists and geologists described zeolite minerals in volcanic, volcaniclastic and sedimentary rocks. Today it is generally accepted that zeolites are widespread minerals, which form in a variety of geological environments. The structure of zeolites is characterized by a framework of linked tetrahedra, each containing of four O atoms at their apices, surrounding Si or Al. This framework contains open cavities in the form of channels and cages, which are usually filled by H2O molecules and extra-framework cations that are commonly exchangeable, (Fig. 1). The channels are large enough to allow the passage of guest molecules. In the hydrated phases, dehydration occurs at temperatures mostly below 400o C and is largely reversible. The zeolite framework may be interrupted by (OH,F) groups; these occupy a tetrahedron apex that is not shared with adjacent tetrahedra [3]. More than 57 natural zeolite species have been recognized so far [4], but only few species occur in large mineable mineral deposits. The most common zeolite species which may occur in mineable deposits are clinoptilolite-heulandite, mordenite, chabazite, analcime, phillipsite, erionite and ferrierite. The commonest commercial deposits consist of clinoptilolite, chabazite and mordenite.

∗

Correspondence Author: Ioannis Marantos, Institute of Geology and Mineral Exploration, Olympic Village, 136 77 Athens, Greece, E-mail: [email protected], [email protected] Vassilis J. Inglezakis and Antonis A. Zorpas (Eds) All rights reserved - © 2011 Bentham Science Publishers Ltd.

Marantos, Christidis and Ulmanu 20

Zeolite formation and deposits

Figure 1: Clinoptilolite structure

ZEOLITE FORMATION Zeolites may form well developed crystals in veins, cavities and vugs of volcanic rocks or as fine grained crystals mainly in volcaniclastic and sedimentary rocks. In the latter cases, zeolites are homogeneously distributed in the mass of volcaniclastic or sedimentary rocks. Regardless the formation mechanism, the zeolite deposits are characterized as “sedimentary deposits” [5]. Volcanic glass (silicic, alkalic, mafic) is the most common parent material of zeolite minerals. Smectite, feldspars, feldspathoiods and biogenic silica may also act as precursors in the formation of zeolite minerals. With increasing temperature certain zeolites, such as the alkaline zeolites clinoptilolite or mordenite, may become unstable and may also act as precursors of stable zeolite species, such as analcime. Zeolites form by a solution/precipitation mechanism and their genesis is controlled by composition, grain size, porosity and permeability of the host rock, temperature, pore water chemistry (pH, salinity, alkalinity), depth of burial, and age of the formation [6, 7]. The role of temperature is a determinative factor in zeolitic alteration, controlling the type of zeolite species which form, as well as the reaction rate. The mineralogical zoning commonly observed in geothermal areas, around intrusive bodies and during burial diagenesis or/and metamorphism is due to the temperature change [8-12 among others]. The chemistry of the mineralizing fluids including pH, the (Na++K+)/H+ and K+/(Na++Ca2++Mg2+) activity ratios and the activities of H4SiO4, Al(OH)4-, Fe2+, Fe3+, H2O and CO2 are additional important factors which may control mineralogical zoning especially in closed systems [6,13-16 among others]. The increase of pressure and temperature by increasing burial in greater depths leads to formation of a vertical zonal arrangement of more to less hydrous zeolites, finally producing metamorphic mineral assemblages [11,17]. The composition of the original material, as well as permeability are also important factors during zeolitic alteration because they determine the type of alteration minerals and the rate of reaction. In the last 60 years, zeolite minerals have been recognized as major constituents of altered volcaniclastic rocks in various geological environments, such as burial metamorphic environments, [17-19], saline alkaline lakes [6, 21-22], marine and fresh water environments; [6,23-24], geothermal environments, etc. The distribution of the alteration mineral phases in various zeolite deposits is usually characterized by zonal patterns depending on the environment of formation.Several genetic classification schemes of zeolites based on the type of geological environment and the hydrologic system have been proposed by

Zeolite formation and deposits

Marantos, Christidis and Ulmanu 21

various authors [25-31]. Following Iizima’s classification scheme [29], the zeolite genetic types can been grouped into four main categories subdivided into various subcategories which are shown below. Zeolite Formed At Elevated Temperatures - The Zones Resulting Primarily By Geothermal Gradients Magmatic Primary Zeolites In some rare cases it has been suggested that analcime may crystallize at the last stages of crystallization of magmatic rocks [32]. However the determination of primary or secondary origin for analcime is difficult; therefore the magmatic origin of analcime still remains controversial [33, 34]. Zeolites Formed By Contact Metamorphic Processes In volcano-sedimentary sequences, concentric alteration zones containing zeolite minerals may be formed around intrusive bodies, as a result of contact metamorphism. A typical case of this type of alteration has been described in the Tanzawa Mountains, Japan, [8]. In this area zeolitic alteration zones have been developed more or less concentrically around a quartz diorite igneous body. Laumontite occurs in the innermost parts and clinoptilolite and stilbite in the outer alteration zones. Hydrothermal Zeolites Various zeolite species may form by hydrothermal activity associated with different types of igneous rocks. This type of deposits includes mainly alteration in active geothermal fields and alteration associated with ore deposition. Zeolites are common alteration minerals in active and fossil geothermal fields with steep geothermal gradients. Typical examples are: the geothermal field of Yellowstone Park in USA, [10], various geothermal fields in Iceland [9], Warakei New Zealand [35], Onikobe in Japan, etc. The formation and distribution of various zeolite minerals in the geothermal fields is controlled by several factors. The temperature is the main controlling factor as it governs the degree of the alteration and the distribution of individual zeolite minerals. Thus in the geothermal field of Iceland all the zeolites are stable at temperature lower than 230°C except for analcime and wairakite that are stable at temperatures up to 300°C [9]. Although mineralogical zoning due to temperature gradients is characteristic for hydrothermal zeolites, it may not be well defined in fields with high geothermal gradients. For example in Iceland zoning is better defined in areas with geothermal gradients lower than 150°C/km compared to areas with gradients higher than 200°C/km [9]. Except for temperature, host rock composition, permeability and geothermal fluid chemistry are also important factors for zeolitic alteration in hydrothermal fields [9, 36]. Zeolite minerals may be formed by mineralizing hydrothermal solutions around ore deposits. A typical example of this environment of formation is the Kuroko-type polymetallic sulfide deposits which form from black smokers on the seafloor. Alteration patterns are rather complex because they are produced by the combined action of submarine hydrothermal alteration and low temperature diagenesis. In this type of alteration, which has been developed on acidic tuffs, the analcime and Na-mordenite hydrothermal zones have been superimposed to the clinoptilolite-mordenite(II) zone of burial diagenesis [37, 38]. Genesis In Geoautoclaves In order to determine the zeolitization of marine ash flow tuffs, in Eastern Rhodope, Bulgaria Aleksiev and Djourova [39] proposed a genetic model that they called “geoautoclave”. In this model vast quantities of ignimbrites were deposited in shallow marine environment in successive short cycles. The deposition of hot pyroclastics in shallow water introduced large amounts of thermal energy in the alteration system. Due to the insulating properties of pumice and volcanic glass an autoclave system was generated favouring the alteration of volcanic glass to zeolites at relatively elevated temperatures. This model is similar to that proposed by Lenzi and Passaglia [40] for the genesis of zeolites in central Italy. The “geoautoclave” model was accepted by several authors in order to interprete zeolite formation in

Zeolite formation and deposits

Marantos, Christidis and Ulmanu 22

ignimbrites [41-44]. Although the “geoautoclave” environment is rather unlikely to occur in nature [45], the temperature of volcanic glass and mainly the rate of cooling are important factors controlling the zeolitization of volcanic tuffs. In volcanic terrains, the presence of magmatic bodies at shallow depths, as well as the volcanic rocks themselves may drive the formation of low temperature hydrothermal solutions, favouring the zeolitization of volcaniclastic rocks, [46-48]. Burial Diagenesis Or Metamorphism In burial diagenetic/metamorphic environments volcaniclastic rocks undergo alteration of volcanic glass to zeolites in thick sedimentary sequences. Due to progressive burial in greater depths a vertical zonal arrangement of alteration mineral assemblages develops, which is controlled mainly by thermal gradients, (Fig. 2). Typical examples of this type of deposits were first described in Triassic sediments in New Zealand [17]. Moreover, well studied zeolite deposits of burial diagenetic type are widespread in the Green Tuff region in Japan. [49-51]. The zeolite formations display a vertical zonal arrangement. With increasing depth the following zones are observed: zone I which is characterized by partly alteration of glass to smectite and opaline silica and the absence of zeolites; zone II that is dominated by the presence of alkali clinoptilolite and alkali mordenite; zone III characterized by transformation of clinoptilolite – mordenite into analcime and laumontite in the lower parts of the zone and zone IV that is characterized by the transformation of analcime to albite. The aforementioned zonal arrengment is controlled mainly by temperature. As indicated by measurements in boreholes in Japanese oilfields the temperature in the boundary between zone I and II i.e the transformation of volcanic glass to alkali-zeolites is 41-50 °C, the boundary between zones II and III, whereby clinoptilolite and mordenite convert to analcime is 84-91 °C and the boundary between zones III and IV is 120-124°C [50,11]. Alteration is affected also by pore water chemistry. Pore fluids of high salinity and alkalinity may lower the temperature of the glass-toalkali zeolite transition to ca 21°C and the clinoptilolite/mordenite transition to about 37°C [11].

Fig. 2: Alteration mineral zoning in burial diagenesis environment, (based on Utada, 1971)

Zeolites Form At Or Near Surface Conditions, The Zones Being Principally Controlled By Chemical Gradients Percolating Groundwater In this alteration type, known also as open system tephra alteration [7], meteoric water percolating through a volcaniclastic pile, reacts with glass, and finally produces vertical zoning of alteration mineral assemblages, including various types of zeolites, clay minerals, authigenic K-feldspar, etc., due to the progressive chemical modification of mineralizing fluids with downward migration. Zeolite deposits of this type hosted in silicic tephra are usually thick. Zeolites in silicic tephra are often formed in depths greater than 200m. Zeolite minerals display usually zonal distribution patterns, (Fig. 3) in a similar way as

Zeolite formation and deposits

Marantos, Christidis and Ulmanu 23

in burial diagenesis, with clinoptilolite, phillipsite and chabazite in the upper part and analcime in the lower zone, [20]. Alteration due to percolating groundwater can be distinguished from alteration due to burial diagenesis because a) the thickness of the glass-to-alkali zeolite zone is significantly more extensive in the latter and b) the time span for alteration is much shorter in the former compared to the burial diagenesis [7]. Typical examples of this type of zeolitization are the John Day Formation, in Oregon USA, [23], Yucca Mountain, Nevada, USA, [52], Trans-Pecos, Texas [53], etc. In the John Day Formation zeolite neoformation takes place below the water table; hence pore fluid migration has an important lateral component [23]. In contrast to acidic tuffs, basic volcaniclastics of basaltic composition may be altered to zeolites and clay minerals. Typical examples of this type of deposits occurs in the Oahu island, Hawaii, where tephra of alkali basalt to nephelinite composition has undergone alteration to palagonite and zeolites, [54], and in northeast Jordan where tephra deposits of alkali olivine basalt composition have been altered to similar end products [55, 56]. The zeolites formed (faujasite, phillipsite and chabazite) have lower Si-contents than clinoptilolite and mordenite. In northeast Jordan three diagenetic zones have been formed having sharp contacts with each other, which follow topography and reflect differences in permeability, flow rate and pore-fluid composition [56].

Figure 3: Alteration mineral zoning in open hydrologic systems

Weathering Various zeolite species have been recognised in soils including clinoptilolite, analcime, chabazite, gismondine, laumontite phillipsite, natrolite and mordenite. Clinoptilolite is the most abundant zeolite found in soils. Although most zeolite occurrences in soils may originate from volcanogenic material such as tuffs, there are soils in which zeolites have neither been inherited into nor formed by the influence of volcanic activity [57]. According to Boettinger and Graham [58], six types of zeolite occurrences have been distinguished in soils: 1) Pedogenic zeolites in saline alkaline soils of non volcanic origin, 2) Pedogenic zeolites in saline alkaline soils of volcanic origin, 3) Lithogenic zeolites inherited from volcanic raw material 4) Lithogenic zeolites inherited from non-volcanic raw material, 5) Lithogenic zeolites from eolian additions and alluvial deposition and 6) zeolites in other soil environments. Alkaline, Saline Lake Deposits

Zeolite formation and deposits

Marantos, Christidis and Ulmanu 24

Saline alkaline lakes are hydrogeologically closed systems, typical of arid or semiarid areas where evaporation exceeds inflow [28, 30, 59]. Saline or saline-alkaline brines may develop by evaporation, depending on parent waters composition and chemical evolution [60, 61]. Modern closed basins are classified into two distinct geological environments a) a playa lake complex in which a broad flat valley is surrounded by a high mountain range and b) a rift system, which is a steep walled, flat, narrow valley [61]. In saline, alkaline lake environments, silicic glass is rapidly altered to zeolite minerals, clay minerals, opaline silica and K-feldspar because of the high pH values, often higher than 9. Clinoptilolite, analcime, chabazite, mordenite, phillipsite and erionite are typical zeolite minerals forming in saline alkaline lakes. The deposits exhibit a lateral zonal distribution of alteration mineral assemblages, due to the zonation of the lake water chemistry from the margins to the centre of the lake. At the margins, where fresh water is trapped in the interstitial pore water of the volcaniclastics, the fresh glass zone exists. The zones of zeolite minerals follow in the interiors of the lake, whereas in the innermost parts where higher pH values prevail, a K-feldspar zone is developed (Fig. 4). In such systems the formation of zeolites from reaction of volcanic glass with alkaline solutions takes place in two steps [62]. First a gel forms, with a Si/Al ratio controlled by the Si/Al ratio of the solution followed by nucleation of zeolites from the gel. The Si/Al ratio of the zeolites is then controlled by the composition of the gel.

Figure 4: Alteration mineral zoning in saline, alkaline lake environment (1. fresh glass zone, 2. zeolite zone, 3. zone of K-feldspar) This type of zeolite deposits is relatively common throughout the world. Typical examples among others include the Pleistocene lake Tecopa, the Pliocene Big Sandy Formation and the Miocene Barstow Formation in USA [63], the Pleistocene lake Olduvai Gorge in Tanzania [64], the Pleistocene – Holocene Lake Magadi in Kenya [65], Lake Natron in Tanzania [6], and the Neogene saline alkaline lake of Karlovassi, Samos Ιsland, Greece [66]. Zeolite minerals may also form in saline environments of low alkalinity. In these cases saline minerals indicative of alkaline waters are absent, Ca-rich zeolites form, and the reaction of Ca-zeolites to form K-felsdpar suggest mobility of Ca [67].

Marantos, Christidis and Ulmanu 25

Zeolite formation and deposits

Zeolites Formed At Low Temperature, Without Recognized Zonation Marine Environment Zeolite genesis is widespread at low temperatures in deep sea sediments. The most common marine zeolites are clinoptilolite and phillipsite. Analcime is next in abundance and numerous other zeolite types such as harmotome, heulandite, mordenite, erionite chabazite gmelinite thomsonite natrolite etc have been identified in various areas [7]. Phillipsite, which is most abundant in sediments younger than the Miocene, usually forms close to the sediment-water interface and disappears at greater depths, possibly because it converts to clinoptilolite. It usually replaces basic volcanic glass in environments characterized by slow sedimentation rates such as the South Pacific [51]. Clinoptilolite is common in sediments of Eocene to Cretaceous age. It forms within the sediment column where silica activity is elevated to stabilize it, mostly from dissolution of opal-A [68]. The source of excess silica is biogenic and occasionally clinoptilolite forms pseudomorphs after radiolaria, even within basic rocks [51, 69]. Analcime has been identified in deep sea sediments, associated with basic rocks. Although it may coexist with phillipsite or clinoptilolite there is not evidence for analcime formation from replacement of these zeolites [7]. Zeolites Formation In Impact Craters Impact Crater Zeolites and clays may form as secondary minerals by reaction of fluids with the shock-derived aluminosilicates and impact glasses within meteorite impact craters. The alteration of glass to zeolites follows the same patterns and is controlled by the same parameters as in the open systems dominated by percolating groundwater. ZEOLITE DEPOSITS AND PRODUCTION Mineable high grade zeolite deposits are widespread in many countries all over the world. Moreover, there are several studies suggesting the efficiency of the zeolite materials in many applications [70-76]. Natural zeolites have not achieved what was predicted in the beginning of 70’s, despite studies that suggest their applicability in numerous agricultural and industrial processes [126]. The same trend is valid till today. Mining of zeolites is performed by open cast methods. Processing is rather simple and includes crushing, screening, and classification to various fractions depending on the application field. In certain cases the zeolite ore may be modified by treatment with acid or salt solutions. The World annual production of zeolites remains generally constant over the last 10 years to ca 3 million tons. The major part of the production is consumed by the cement industry for the manufacture of pozzolanic cement. The world production for 2008 was 2.5 -3 million metric tons (Mt), with individual countries production to be assigned as shown in Table 1. Table 2 lists some geological data, zeolite content and physical properties of selected zeolite deposits under exploitation in the main production countries. Table 1: World production of zeolites, Virta (2008) [77] COUNTRY China Jordan the Republic of Korea Japan Turkey USA Slovakia Indonesia Ukraine Hungary New Zealand

PRODUCTION (thousand tn) 1750 to 2250 (including pozzolan applications) 400 to 450 (including pozzolan applications) 160 140 to 160 (including pozzolan applications) 100 60,1 60 30-50 (including pozzolan application) 20-40 20 to 30 17

Zeolite formation and deposits

Cuba Bulgaria South Africa Australia Spain Canada, Greece, Italy, the Philippines, and Russia Mexico Argentina, Germany (excluding pozzolan applications), Serbia, and Slovenia

Marantos, Christidis and Ulmanu 26

16,5 15 10 5-10 5-10 3 to 5 each 0,7 probably less than 1 to 2

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Zeolite formation and deposits

Table2: Geological data of selected zeolite deposits Country Australia

Bulgaria

China

China

Location Werris Creek, New South Wales

Commodity Clinoptilolite,

Quirindi, Castle Mountain, New South Wales

Clinoptilolite

Willows, Queensland

Clinoptilolite

Beli Plasti Eastern Rhodopes HaskovoKardzhali Jelezni Vrata, Eastern Rhodopes, Kardzhali Dushikou Mine, Chi-cheng county, Hebei Province Jin-yun county mine, Zhejiang Province Hai-ling County Heilongjiang Province Xinyang City

Clinoptilolite

Grade Clinoptilolite and minor mordenite >60%. CEC 1.2 meq/g Zeosand 85% clinoptilolite CEC 1.47meq/g Zeobrite 54% clinoptilolite CEC 1.19meq/g 50% zeolite

Clinoptilolite 5295%, CEC 1.13-1.51 meqNH4/g

Geological characteristics Late Carboniferous, Escott zeolite formation cosists of massive-laminated lacustrine mudstones- water-lain, ash fall vitric tuffs, red to green Late Carboniferous, Escott zeolite formation cosists of massive-laminated lacustrine mudstones- water-lain, ash fall vitric tuffs, red to green

Mining Co Zeolite Australia P/L

Reference [42,78,79,80]

Castle Mountain Enterprises Pty Ltd

[81,82]

Drummond basin: basal Late Devonian shallow marine sedimentary rocks, overlain by Early Carboniferous fluvial and lacustrine sediments and silicic volcanics.The major zeolite unit is the Ducabrook formation. Water lain, ash fall tuffs. Lower Oligocene zeolitised ash flow (massive tuffs) -

Supersorb

[78,83,84]

S&B Industrial Minerals S.A.

[46]

zeolitised pumice flows (massive weakly welded ignimbrites) + zeolitized fall-out tuffs (bedded) – clinoptilolite

Trasingeneering (Bulgarian) – production for cement.

[85, 47, 86]

Clinoptilolite

50-70% zeolite (400Mt)

[87]

Clinoptilolite with minor mordenite

>100Mt

[87]

>65% zeolite >100Mt

[87]

Zeolite

Broad Xinyang Mining Co

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Zeolite formation and deposits

Cuba

Germany Hungary

Zhejiang Shenshi Henan China

powder zeolite Zeolite

Fujian China Tianjin

Clinoptilolite

Tsagaantsav, Mongolie Govi-Tamsag, Mongolia

Clinoptilolite Clinoptilolite

Clinoptilolite 8085% Clinoptilolite 8096% 30-70% zeol

Govi-Tamsag, Mongolia

Clinoptilolite

10-80% zeol

Caimanes, Moa, Holguin Bueycito, Bayamo Granma Prov Palenque, Guantanamo Poijilo, Santa Clara Tasajeroas Santa Clara Chucho Rojas Conductora Joaquina Carolinas, Cienfuegos Los Congos deposit, Mariel region Kaiserstuhl, SW Germany Mad-Suba

clinoptilolite

Zhejiang Shenshi Mining Industry Co, Ltd., Huai zeolite powder Xinyang Industry Co.Ltd Gongyi Zhongdatong Water Material Co, Ltd Changsha Xian Shan Yuan Agriculture & Technology Co, Ltd Esytun Industrial Ltd Tianjin Bentonite Minchem Co, Ltd

[88]

Dorniin Zeolite LLC Zeolite beds and stratum occurring in siliceous tuff, tuffaceous sandstone and argillite of the Early Cretaceous Tsagaantsav formation. Early Cretaceous zeolite beds. Can be broken into three productive horizons with a content of 70-90% zeolite (clinoptilolite). Altered Paleogene volcaniclastics

[89]

mordenite

Zeolitized Paleocene –middle Eocene Massive volcaniclastics of intermediate composition

[90]

Clinoptilolite, mordenite

Zeolitized Paleocene –middle Eocene Sabaneta formation Cretaceous

[90]

Cretaceous

[90]

Cretaceous Cretaceous Cretaceous Cretaceous

[90] [90] [90] [90]

Heulandite type zeolites

[89]

[90]

[90]

[91]

Zeolites

45%zeolite

Miocene Kaiserstuhl volcanic Comlex

Hans G. Hauri Mineralstoffwerk

[92]

Clinoptilolitic

Clinoptilolite 25-35

Altered sarmatian rhyolitic tuffs

Geoproduct

[93]

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Zeolite formation and deposits

tuffs

Indonesia

Japan

Jordan

Ratka

Clinoptilolitic tuffs

Bodrogkeresztur

Mordenitic tuffs

Mad-Vasut Mount Rataiand Tarahan, Lampiung Province, Sumatra Panjung, Lampung Province Java Oshyamambe, Hokkaido Futatsui, Akita Pref Itaya, Yamagata Pref Nishiaizu, Fukushima Pref., Iwami Mine, Shimane Pref. Itado, Akita Pref. Maji, Shimane Pref Iizaka Shiroise Itaoroshi Rashadieh Tel Remah Tel Hassan

%, Montmorillonite 25-35%, glass 2530% Clinoptilolite>40%, average 55%,glass