Ferrierite Series


Ferrierite-Mg		\|Mg_0.5K, Na, Ca_0.5)₆(H₂O)₂₀\| [Al₆Si₃₀O₇₂]
Ferrierite-K		\|K, Na, Mg_0.5, Ca_0.5)₆(H₂O)₂₀\| [Al₆Si₃₀O₇₂]
Ferrierite-Na		\|Na, K, Mg_0.5, Ca_0.5)₆(H₂O)₂₀\| [Al₆Si₃₀O₇₂]

Morphology:			Clusters of ferrierite-Mg blades from the type locality at Kamloops Lake, British Columbia, Canada. Width of view 10 mm.
	Orthorhombic mmm bladed crystals elongated on [001] with the forms {100}, {010}, and {101}

Physical properties:
	Cleavage: {100} perfect Hardness: 3 –3.5 Density: 2.136 g/cm³ Luster: vitreous Streak: white


Optical properties:
	Color: colorless, white, yellowish, pinkish, orange to red; colorless in thin section Biaxial (+ or -) α = 1.473-1.488, β = 1.474-1.489, γ = 1.477-1.491, δ = 0.004-0.007 2V_z = 50-145° X = a, Y = b, Z = c (length slow) Dispersion: r < v, weak

Crystallography:
	Unit cells:
	Ferrierite-Mg	a = 18.231(2) Å, b = 14.145(2) Å, c = 7.499(1) Å, Z = 1 average space group Immm; true space group Pnnm (Alberti and Sabelli, 1987) Monastir, Sardinia
	Ferrierite-K	a = 18.973(7) Å, b = 14.140(6) Å, c = 7.478(4) Å, Z = 1 average space group Immm (Wise and Tschernich, 1976) Santa Monica Mtns., Los Angeles County, California, USA
	Ferrierite-Na	a = 18.886(9) Å, b = 14.182(6) Å, c = 7.470(5) Å, β = 90.0°, Z = 1 space group P2₁/n (Gramlich-Meier et al., 1985) Altonia, Washington, USA

Names:
	Ferrierite was described and named by Graham (1918) to honor Walter F. Ferrier, mineralogist, mining engineer, and one-time member of the Geological Survey of Canada, who first collected the material on the north shore of Kamloops Lake, British Columbia, Canada. The International Mineralogical Association (Coombs et al., 1997) has elevated the name to series status to include three species with the same crystal structure but different compositions. Ferrierite-Mg is the new name for the original material, in which Mg is the most abundant non-framework cation. Ferrierite-Na is a new species with the type example from Altoona, Wahkiakum County, Washington, and ferrierite-K is a new species with the type example from the Santa Monica Mountains, Los Angeles County, California, USA.

Crystal structure:
	Ferrierite may be orthorhombic, space group Immm, which agrees with the maximum symmetry of the framework topology (Vaughan, 1966; Gramlich-Meier et al., 1984). Gramlich-Meier et al., 1985) refined the structure of ferrierite-Na (Mg-poor) in space group P2₁/n (standard setting P2₁/c). In contrast to the orthorhombic structure, monoclinic ferrierite-Na has no T-O-T angles of 180°. In light of the discussion on the mordenite, dachiardite, and epistilbite structures, it may be speculated that lower symmetry is a general feature of all ferrierite (Alberti, 1986; Alberti and Sabelli, 1987). Alberti and Sabelli (1987) refined the structure of ferrierite-Mg from Monastir, Sardinia, in space group Immm but provided strong evidence, based on disorder of the Mg(H₂O)₆²⁺ non-framework complex, that the true space group is Pnnm, which leads to a relaxation of the 180° T-O-T angle. Thus, the straight T-O-T angle must only be apparent because of statistical occupation. The monoclinic symmetry (Gramlich-Meier et al., 1985) seems to be specific for the Mg-poor species. Both monoclinic and orthorhombic ferrierite display pronounced streaking of single-crystal X-ray reflections parallel to [010]* and [110]* caused by contraction and expansion faults (Gramlich-Meier et al., 1984; Smith, 1986).


		The structure of ferrierite using atom positions of Vaughan (1966), projected onto (001). Na⁺ (red circles) and low occupancy sites (light blue) are in the 10-ring channels. Mg²⁺ (yellow) with H₂O molecules (dark blue) of the Mg(H₂O)₆²⁺ complex are in the [010] channels and between 6-rings in this view. The black dots locate the inversion centers in the Immm space group.

The structure of ferrierite (FER and the figure above) can be envisioned as corrugated six-membered ring sheets (parallel to (100)) with the same arrangement of up and down tetrahedra as in dachiardite (DAC) and epistilbite (EPI). However, the sheets in ferrierite, which also define the perfect cleavage, are connected parallel to the a-axis by six-membered rings and not by four-membered rings as in the dachiardite and epistilbite. This arrangement leads to channels parallel to the c-axis formed by ten-membered rings (aperture 5.4 x 4.2 Å) interconnected by channels, parallel to the b-axis, confined by eight-membered rings (aperture 4.8 x 3.5 Å). Mg forms a disordered Mg(H₂O)₆²⁺ complex wedged in between six-membered in the channels parallel to the b-axis. Alkali ions are disordered in the wide channels parallel to the c-axis.


Chemical composition:

	Ferrierite has long been known as the zeolite with major amounts of Mg, and only a few of the more recent discoveries have had alkali cations in dominant amounts. The compositional range of analyzed ferrierite is shown in the figures below. TSi ranges from 0.76 to 0.86 (27.5 to 31 Si per unit cell) and varies inversely with the total number of divalent cations, mostly Mg. The two hydrated Mg sites per cell are filled in most ferrierite-Mg samples, but the alkali dominant compositions contain less than one Mg per cell. Ca varies from zero to one cation per cell; Ba abundance varies up to 0.4, and Sr is seldom present.

	Diagrams illustrating the compositional range of ferrierite series minerals. The two green circles represent ferrierite from Tertiary lacustrine deposits in Nevada, USA. All others are from cavities or fractures in altered basaltic and andesitic rocks.

	There has been some disagreement on the amount of H₂O molecules contained within a unit cell of ferrierite, varying from 18 to 20. The complete analyses, compiled by Deer et al. (2004) have total water amounts of nearly 15 weight percent, and the weight loss in the thermal gravimetric analysis by Gottardi and Galli (1985) is also about 15%. This value indicates 22 H₂O molecules per unit cell. The average water content from those analyses with water determinations is about 13.6%, which corresponds to about 20 molecules per unit cell. It is this amount that is given in the average formulae given above, but it is likely that saturated ferrierite may contain as many as 22 molecules.


Occurrences:
	Ferrierite is a fairly rare zeolite with about 30 known localities. Most of these occurrences are in fractures or other cavities in altered basalt or andesite. There are several occurrences of ferrierite as diagenetic replacement of rhyolitic pyroclastic sediment in the U.S., Korea, and Japan. In all occurrences ferrierite is closely associated with other high-silica zeolites, commonly mordenite and clinoptilolite, as well as opal or chalcedony and calcite. Temperatures of formation range from the surface conditions of lakes in arid climates to that of weak hydrothermal systems (120° to 150°C). The following is adapted from Deer et al. (2004).
	Diagenesis of sediment and sedimentary rocks
	Ferrierite has been recognized in two kinds of diagenetic settings of sedimentary rock, one in rhyolitic tuff interbedded with lacustrine sediment and the other in andesitic sediment in near arc basins.
	Hydrologically closed systems
		Two occurrences of diagenetic ferrierite in rhyolitic pyroclastic sediment, that are at least in part lacustrine, are in northwestern Nevada, USA, in the Trinity Range northwest of Lovelock, Pershing County and in the Stillwater Range near Fallon, Churchill County (Sand and Regis, 1968; Rice et al., 1992). Because of limited exposures, there is little evidence of the lateral variation of zeolite species typical alteration of tuff in saline, alkaline lakes. Nonetheless, the ferrierite is thought to have that type of origin. Cores drilled through the zeolitic beds at the Lovelock occurrence recovered fresh glass at the base of a vitric tuff. Zeolite abundance increases upward into thick ferrierite beds, which are overlain by increasingly higher contents of mordenite (Rice et al., 1992). In a similar occurrence, rhyolitic tuffaceous rocks probably deposited in a lacustrine setting in the Sangjeongdong district, Yeongil area, Korea, are variably replaced with ferrierite in association with mordenite (Noh and Kim, 1986).
	Marine sediment from arc-source terrains
		In the Green Tuff region of Japan zeolite distribution is related either to depth of burial or proximity to intrusions, giving a sequence of zones formed by diagenesis into very low-grade metamorphism. Zones of burial diagenesis and metamorphism as defined by Iijima and Utada (1972) are: I: altered glass zone; II: alkali clinoptilolite zone; III: clinotpilolite-mordenite zone; IV: analcime zone; and V: albite zone. Where ferrierite occurs, it is associated with mordenite in Zone III. Using geothermal gradients from oil fields in this region, Iijima and Utada (1972, Fig. 8) suggest that the lower limit of zone III is about 50°C and the upper limit, about 90° C.
		Ferrierite with clinoptilolite and mordenite comprises up to 40% of Miocene altered tuff beds at Tadami-machi, Fukushima Prefecture (Hayakawa and Suzuki, 1969). Other occurrences are in tuff at Futatsumori, Akita Prefecture and Kobayashi, Fukushima Prefecture (Nambu, 1970). Occurrences associated with Kuroko-type ore deposits are described below.
	Diagenesis of mafic lava flows
		Most of the known ferrierite occurrences are associated with altered basalt or andesite flows and flow breccia. It is apparent that the host rock must have fairly high silica content, as well as magnesium. In many cases the alteration is so extensive that distinguishing between diagenetic and hydrothermal alteration is not possible. Some of the important occurrences are the following.
		At the type locality at Kamloops Lake, British Columbia, Canada, abundant ferrierite-Mg occurs in cavities of altered flow breccia of Miocene olivine basalt (Graham, 1918). It is associated with chalcedony, quartz, calcite, and rarely clinoptilolite-Na. Other occurrences in British Columbia are in relatively fresh, middle Tertiary basalt at Monte Lake and in altered basalt at Pinaus Lake, both in the Kamloops District. The type example for ferrierite-Na comes from Altoona, Washington (Wise and Tschernich, 1976), where it occurs with mordenite and clinoptilolite in vesicles of glassy, tholeiitic basalt (Miocene, Columbia River Basalt). The type example for ferrierite-Mg is from calcite filled veins cutting deeply weathered porphyritic volcanic rock at Albero Bassi, Vicenza, Italy (Alietti et al., 1967).
		Ferrierite-K occurs in several localities in the vicinity of Agoura (in the Santa Monica Mountains), Los Angeles County, California, USA (Wise et al., 1969), one of which is the locality for the type-example of the species. The host rock is Miocene porphyritic andesite breccia with a glassy groundmass. Associated minerals are clinoptilolite-Na, chalcedony, and opal.
		Several other ferrierite occurrences are in veins cutting thick sections of weakly altered basalt and andesite, such as Silver Mountain, Alpine County, California, USA (Wise and Tschernich, 1976), and Monbetsu, Hokkaido, Japan. Host rocks in these occurrences show no evidence of hydrothermal leaching, so that ferrierite is interpreted as having been deposited from post-magmatic fluids (Matsubara et al., 1996). Ferrierite with harmotome, heulandite, chlorite, and carbonates occur in hydrothermal veins cutting picrite of the teschenite association at Honcova hurka near Pribor, northern Moravia, Czech Republic (Kudelaskova et al., 1990).
	Hydrothermal alteration
		Ferrierite is a rare mineral in the hydrothermal aureoles surrounding Kuroko-type deposits in northern Honshu, Japan (Utada, 1988). It occurs sporadically and in veinlets within the mordenite zone, the outermost of several zones. The hydrothermal zones are thought to have formed after the ores were deposited and covered with sediment. The capping sediment allowed cooling hydrothermal waters to spread outward, becoming alkaline and allowing zeolite crystallization. The temperatures of ferrierite formation are probably consistent with that of the mordenite-clinoptilolite zone of diagenesis, less than 120-150°C.
		Ferrierite with mordenite and dachiardite-Na occurs on joint surfaces and in cavities in chlorite schist and amphibolite in the tunnels through Tanzenberg near Kapfenberg, Styria, Austria (Postl et al., 1985). This type of occurrence in non-volcanic host rocks suggests the zeolite grew in warm fluids flowing through the fracture system.

References:
	Alberti, A. (1986) The absence of T-O-T angles of 180° in zeolites. In Y. Murakami, A. Iijima, and J.W. Ward, eds: New Developments in Zeolite Science Technology. Proc. 7th Int’l Zeolite Conf., 437-441. Alberti, A. and Sabelli, C. (1987) Statistical and true symmetry of ferrierite: possible absence of straight T‑O‑T bridging bonds. Z. Kristallogr. 178, 249-256. Alietti, A., Passaglia, E., and Scaini, G. (1967) A new occurrence of ferrierite. Am. Miner. 52, 1562-1563. Coombs, D.S., Alberti, A., Armbruster, T., Artioli, G., Colella, C., Galli, E., Grice, J.D., Liebau, F., Mandarino, J.A., Minato, H., Nickel, E.H., Passaglia, E., Peacor, D.R., Quartieri, S., Rinaldi, R., Ross, M., Sheppard, R.A., Tillmanns, E., and Vezzalini, G. (1997) Recommended nomenclature for zeolite minerals: Report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. Can. Min. 35, 1571-1606. Deer, A., Howie, R., Wise, W.S., and Zussman, J. (2004) Rock Forming Minerals. vol. 4B. Framework Silicates: Silica Minerals, Feldspathoids and the Zeolites. The Geological Society, London. Gottardi, G. and Galli, E. (1985) Natural Zeolites, Springer-Verlag, Berlin, Germany. 409 pp. Graham, R.P.D. (1918) On ferrierite, a new zeolitic mineral, from British Columbia; with notes on some other Canadian minerals. Trans. Roy. Soc. Can., Ser. 3, 12, 185-201. Gramlich-Meier, R., Meier, W.M., and Smith, B.K. (1984) On faults in the framework structure of the zeolite ferrierite. Z. Kristallogr. 169, 201-210. Gramlich-Meier, R., Gramlich, V., and Meier, W.M. (1985) The crystal structure of the monoclinic variety of ferrierite. Am. Miner. 70, 619-623. Hayakawa, N. and Suzuki, S. (1969) Zeolitized tuffs and occurrences of ferrierite in Tadami-Machi, Fukushima Prefecture. Japan Mining Geol. 20, 295-305. Iijima, A. and Utada, M. (1972) A critical review on the occurrence of zeolites in sedimentary rocks in Japan. Japan. J. Geol. Geogr. 42, 61-83. Kudelaskova, M., Kudelasek, V., and Matysek, D. (1990) Zeolites in the picrite of the tschenite association at the locality Honcova Hurka near Pribor (northern Moravia). Casopis pro Mineral. Geol. 35, 317-321. Matsubara, S.; Tiba, T., Kato, A,. and Shimizu, M. (1996) Ferrierite from Monbetsu, Hokkaido, Japan. Mineral. Jour. 18, 147-153. Nambu, M. (1970) Introduction to Japanese mineralogy. Geological Survey of Japan. Tokyo. Noh, J.H. (1985) Mineralogy and genesis of zeolites and smectites from Tertiary tuffaceous rocks in Yeongil area (Korea). Dissertation, Dept. of Geol. Sci., Seoul National University, 129 pp. Noh, J.H. and Kim, S.J. (1986) Zeolites from Tertiary tuffaceous rocks in Yoengil area, Korea. In New developments in zeolite science and technology, 28,. Proc. of the Seventh Int. Zeol. Conf., ed. Murakami, Y., Iijima, A., and Ward, J.W., Kondansha and Elsevier, Tokyo, 59-66. Postl, W., Walter, F., Moser, B., and Golob, P. (1985) Die Mineralparagenesen aus der Südröhre des Tanszenbergtunnel bei Kapfenberg, Steiermark. Mitt. Abt. Miner. Landesmuseum Joanneum 53, 23-48. Rice, S.B., Papke, K.G., and Vaughan, D.E.W. (1992) Chemical controls on ferrierite crystallization during diagenesis of silicic pyroclastic rocks near Lovelock, Nevada. Am. Miner. 77, 314-328. Sand, L.B. and Regis, A.J. (1968) Ferrierite, Pershing County, Nevada. In Abstracts for 1966, Geol. Soc. Amer., Sp. Pap. 101, 189. Smith, B.K. (1986) Variations in the framework structure of the zeolite ferrierite. Am. Miner. 71, 989-998. Utada, M. (1988) Occurrence and genesis of hydrothermal zeolites and related minerals from the Kuroko-type mineralization areas, Japan. In, Kalló, D. and Sherry, H.S. (eds.) Occurrence, Properties and Utilization of Natural Zeolites. Akadémiai Kiadó, Budapest, 39-48. Vaughan, P.A. (1966) The crystal structure of the zeolite ferrierite. Acta Crystallogr. 21, 983-990. Wise, W.S., Nokleberg, W.J,. and Kokinos, M. (1969) Clinoptilolite and ferrierite from Agoura, California. Am. Miner. 54, 887-895. Wise, W.S. and Tschernich, R.W. (1976) Chemical composition of ferrierite. Am. Miner. 61, 60-65.