The Lavrion area corresponds to the western part of the Attic-Cycladic metamorphic belt, in the back-arc region of the active Hellenic subduction zone. Between the Eocene and the Miocene, metamorphic rocks (mainly marbles and schists) underwent several stages of metamorphism and deformation due to collision and collapse of the Cycladic belt. Exhumation during the Miocene was accommodated by the movement of a large-scale detachment fault system, which also enhanced emplacement of magmatic rocks, leading to the formation of the famous Lavrion silver deposits. The area around the mines shows the stacking of nappes, with ore deposition mainly localized within the marbles, at marble-schist contacts, below, within, or above the detachment. The Lavrion deposit comprises five genetically-related but different styles of mineralization, a feature never observed in another ore deposit elsewhere, containing the highest number of different elements of any known mining district. The local geology, tectonic, and magmatic activity were fundamental factors in determining how and when the mineralization formed. Other key factors, such as the rise and the fall of sea level, which resulted from climate change over the last million years, were also of major importance for the subsequent surface oxidation at Lavrion that created an unmatched diversity of secondary minerals. As a result, the Lavrion deposit contains 638 minerals of which Lavrion is type-locality for 23 of them, which is nearly 12% of all known species. Apart from being famous for its silver exploitation, this mining district contains more minerals than any other district on Earth. The unique geological, mineralogical, and educational (mining, archaeological, and environmental) features suggest that it is highly suitable to be developed as a future UNESCO Global Geopark.

This paper examines the lithology and raw material provenance of knapped stone artifacts recovered from prehistoric sites on Meganisi in the course of the Inner Ionian Sea Archipelago survey. Research was twofold: in the field to map the geology of the island and collect raw material samples, and in the laboratory to conduct a petrological study using LM, XRD, SEM and ICP-MS techniques. The greater part of the materials used to produce stone tools consists of almost pure SiO2, bedded or nodular cherts mainly of Malm–Turonian and Eocene ages. The cherts were collected by prehistoric knappers from local sources. Patinas present on the artifacts are relatively enriched in calcite material of incomplete silica diagenesis and subsequently a product of late weathering and alteration.

The crystal structure (R = 0.0750) of fiedlerite-1A Pb3Cl4F(OH) H2O from ancient slags of Lavrion (Greece) was studied on a single crystal. The mineral is triclinic, a = 8.5741(7), b = 8.0480(5), с = 7.2695(4) Å, (a = 90.087(5), (b = 102.126(6), (g = 103.424(6)) V = 476.37(6) Å3, Z = 2. Pb2+ cations centre bicapped trigonal prisms Pb(1)F(H2O)Cl6, Pb(2)(OH)2FCl5 and Pb(3)(OH)F2Cl5. Additional Pb′site with 10% occupancy was revealed in the structure. There are two basic structure fragments alternating along the a axis: (100) layers formed by Pb(2)- and Pb(3)-centred polyhedra and elongated along the b axis zig-zag chains formed by Pb(1)-centred polyhedra sharing common edges. IR spectrum of fiedlerite-1A is given.

In the Hellenides Orogen, minerals of various gem quality occur in various rock types from mainly four tectono-metamorphic units, the Rhodope, Pelagonian, and the Attico-Cycladic massifs, and the Phyllites-Quartzites unit of Crete Island. In crystalline rocks, gemstones are related to both regional metamorphic-metasomatic processes (e.g., gem corundums, Mn-andalusite, thulite/clinothulite, spessartine, titanite, jadeite), and to the formation of late alpine-type fissures, such as, for example, quartz, albite, adularia and titanite. The Tertiary (and Mesozoic) magmatic-hydrothermal environments provide gem-quality sapphire, beryl, garnet, vesuvianite, epidote, fluorite, and SiO2 varieties. The supergene oxidation zone of the Lavrion deposit hosts gem-quality smithsonite and azurite. Coloration in the studied material is either due to various chromophore trace elements present in the crystal structure, or due to inclusions of other mineral phases. Future modern exploration methods combined with gemological investigations (such as treatment and faceting of selected stones), are necessary in order to obtain a better knowledge of the gemstone potential of Greece for its possible exploitation.

ABSTRACTThe hydrocerussite-related phase, NaPb5(CO3)4(OH)3, has been found as colourless lamellar crystals in cavities within a pebble of the ancient marine slag collected in the Pacha Limani area of the Lavrion mining district, Attiki, Greece. This phase of anthropogenic origin was characterized by electron microprobe, infrared spectroscopy, powder and single-crystal X-ray diffraction. The unique crystal structure (P63/mmc,a= 5.2533(11),c= 29.425(6) Å,V= 703.3(3) Å3andR1= 0.047) is based upon structurally and chemically different electroneutral blocks. Each of the blocks can be split into separate sheets. The outer sheets in each block are topologically identical and have the composition [PbCO3]0. The [Pb(OH)2]0lead hydroxide sheet is sandwiched between the two [PbCO3]0sheets resulting in the formation of the first block [Pb3(OH)2(CO3)2]0structurally and compositionally identical to that one in hydrocerussite Pb3(OH)2(CO3)2. Similarly the [Na(OH)]0sheet is sandwiched between another two [PbCO3]0sheets thus forming the [NaPb2(OH)(CO3)2]0block described previously in the structure of abellaite NaPb2(OH)(CO3)2. Stereochemically active lone electron pairs on Pb2+cations are located between the blocks. There are two blocks of each type per unit cell, which corresponds to the following formula: [Pb3(OH)2(CO3)2][NaPb2(OH)(CO3)2] or NaPb5(CO3)4(OH)3in the simplified representation. The formation of NaPb5(CO3)4(OH)3in Lavrion slags is by the contact of lead-rich slags with the sea water over the last two thousand years.

Anthropogenic vanadates with garnet structure were found in old metallurgical slags from the Lavrion mining dis-trict in Greece. They occur as brownish to blackish isometric crystals up to 2 mm across and are associated with anthropogenic counterparts of liebenbergite, trevorite, bannermanite, albite, nosean, hatiyne, etc. The studied vanadate garnets form a terna-ry solid-solution system with the end-members {NaCa2}[Mg-2](V5+3)O-12 (mineral name schaferite), {NaCa2}[Ni-2](V(5+)3)O-12 and {Na-3} [Fe-3+2](V35+O12. The main scheme of heterovalent isomorphous substitutions is: Na++Fe3+ Ca2+ M2+, with M2+= Mg, Ni. The crystal structures of two crystals with different Mg:Ni ratio, {Na1.5Ca1.5}(Sigma 3)[Mg1.1Fe0.53+Ni (0.4) ](Sigma 2) (V P-2.8 (0.2))(Sigma 2) O (12) (1) and {Ca1.7Na13}(Sigma 3)[Ni-1.0 Mg0.7Fe0.33+](Sigma 2)(V2.8P0.2) O-Sigma 3(12) (2), were studied. Both are cubic, space group Ia-3d, with a =12.388(3) angstrom (1) and 12.387(3) angstrom (2), V=1901.1(14) angstrom(3) (1) and 1900.6(2) angstrom(3) (2) and Z= 8. Final R values are 0.0245 for (1) and 0.0237 for (2).

The fumarolic mineralogy of the Icelandic active volcanoes, the Tyrrhenian volcanic belt (Italy) and the Aegean active arc (Greece) is investigated, and literature data surveyed in order to define the characteristics of the European fumarolic systems. They show broad diversity of mineral associations, with Vesuvius and Vulcano being also among the world localities richest in mineral species. Volcanic systems, which show recession over a longer period, show fumarolic development from the high-temperature alkaline halide/sulphate, calcic sulphate or sulphidic parageneses, synchronous with or immediately following the eruptions, through medium-temperature ammonium minerals, metal chlorides, or fluoride associations to the late low-temperature paragenesis dominated by sulphur, gypsum, alunogen, and other hydrous sulphates. The situation can be different in the systems that are not recessing but show fluctuations in activity, illustrated by the example of Vulcano where the high-temperature association appears intermittently. A full survey of the mineral groups and species is given in respect to their importance and appearance in fumarolic associations.

Rodafnidia is an Acheulian site on Lesbos Island, in the north-east Aegean Sea. This chapter presents the model that guided Paleolithic investigations on the island, the history of research, and the results of the 2012 expedition of systematic work in the field, which consisted of surface survey and excavation. The typology and technology of lithic artifacts from the surface and the uppermost Unit 1, as well as the first cluster of luminescence dates, firmly place the early component of the site in the Middle Pleistocene. The Acheulian industry derives from fluvio-lacustrine deposits at a locale with abundant fresh-water and lithic resources. Situated in the north-east Mediterranean Basin, an area where research on early hominin prehistory is intensifying, Rodafnidia holds the potential to contribute to Eurasian Lower Paleolithic archaeology and fill the gap in our understanding of early hominin presence and activity where Asia meets Europe.

A new tsumcorite-group mineral, nickeltsumcorite, Pb(Ni,Fe)2(AsO4)2(H2O,OH)2, the Ni-dominant analogue of tsumcorite and cobalttsumcorite, was found in the oxidation zone of a hydrothermal orebody containing gersdorffite and galena at the Km-3 mine, Lavrion, Attikí Prefecture, Greece. It is associated with annabergite, nickellotharmeyerite, nickelaustinite, gaspéite, calcite, dolomite, aragonite, quartz, goethite, cerussite, arseniosiderite, mimetite, oxyplumboroméite and Mn oxides/hydroxides. Nickeltsumcorite occurs as open-work aggregates and interrupted crusts up to 3 mm × 5 mm in area and up to 0.2 mm thick. They typically consist of coarse radial spherulites or dense concentric nodules up to 0.15 mm in diameter. Bunches or hemispherical clusters of crude individuals and separate imperfect, elongated crystals (up to 0.02 mm long) are also observed. Nickeltsumcorite is yellow, brownish-yellow, light brown or brown, with a yellow streak and a vitreous lustre. The Mohs hardness is ∼4. The mineral is brittle; one direction of distinct cleavage is observed under the microscope. D(calc.) = 5.02 g cm. Nickeltsumcorite is optically biaxial (–), α = 1.82(2), β = 1.87(1), γ = 1.90(1), 2V(obs.) is large. The chemical composition (wt.%, electron-microprobe data, H2O by difference) is CaO 2.79, PbO 28.12, MgO 0.30, CoO 0.15, NiO 17.39, ZnO 0.76, Mn2O3 0.57, Fe2O3 6.83, As2O5 38.17, H2O 4.92, total 100.00. The empirical formula, calculated based on 10 O apfu, is (Pb0.76Ca0.30)Σ1.06(Ni1.39Fe 3+ 0.51Zn0.06Mn 3+ 0.04 Mg0.04Co0.01)Σ2.05As1.99O7.97[(H2O)1.25(OH)0.78]. The strongest reflections in the powder X-ray diffraction pattern [d,Å(I )(hkl)] are 4:64 100 ð Þ(111), 4:47 41 ð Þ(201), 3:238 82 ð Þ(112), 3.008(60)(201), 2.859(41)(021), 2:545 79 ð Þ(312, 112), 2:545 79 ð Þ(312, 112) and 2:505 61 ð Þ(220, 203). The cation composition, powder Xray diffraction data and IR spectrum show that nickeltsumcorite belongs to the tsumcorite structure type. The newmineral is monoclinic, space groupC2/m, a = 9.124(8), b = 6.339(3), c = 7.567(7) Å, β = 115.19(6)°, V = 396.0(7) Å and Z = 2. Nickeltsumcorite forms a solid-solution series with nickellotharmeyerite.

However, other sigillata workshops were de nitely located in extra-urban contexts: Capolona, Isola di Migliarino, Castiglioncello, Torrita di Siena, Marzuolo, Vasanello, and Scoppieto

A novel Ni-Mg-analogue of lyonsite, Cu3+x(Fe-4-2x(3+) Cu-2x)(VO4)(6) (0 <= x <= 1), with substitution of Ni and Mg for Cu (below: NMAL) was found in old metallurgical slags from the historical Lavrion mining district in Greece. NMAL forms reddish-black, with semimetallic lustre, prismatic to acicular crystals up to 1 mm long and up to 0.2 mm thick and is associated with anthropogenic counterparts of liebenbergite, trevorite, schaferite, bannermanite, albite, nosean, haune and others. The crystal structure of NMAL was solved from single-crystal X-ray diffraction data (298 K), R = 0.0238. NMAL is orthorhombic, Pnma, a = 4.9573(3), b = 10.1672(8), c = 17.1605(12) angstrom, V = 864.92(11) angstrom(3). Its chemical composition, determined by electron microprobe, is: MgO 5.71, NiO 19.62, ZnO 0.84, Al2O3 0.84, Mn2O3 0.24, Fe2O3 18.43, SiO2 0.06, TiO2 1.82, P2O5 0.38, V2O5 51.77, total 99.72 wt.%. The formula derived from both the crystal structure and electron microprobe data is (Z = 2):(A(1))(Fe2.483+Ni1.28Ti0.12Al0.12)(Sigma 4) (A(2))(Mg1.22Ni0.44Zn0.10)(Sigma 1.76) (A(2'))(Mg0.16Ni0.06Zn0.02)(Sigma 0.24) (A(3))(Ni0.54Ti0.08Al0.02 square(0.28))(Sigma 0.92) (A(3'))(Ni0.62Ti0.08Al0.04 square(0.34))(Sigma 1.08)(VO4)(6) (calculated on the basis of 24 O atoms). The bulk formula of NMAL is (Ni2.94Fe2.483+Mg1.38Ti0.28Al0.18Zn0.12 square(0.62))(Sigma 8)(VO4)(6) and the simplified crystal-chemical formula is (Ni,square)(2)(Mg, Ni)(2)(Fe3+, Ni)(4)(VO4)(6).

A new tsumcorite-group mineral, nickeltsumcorite, Pb(Ni,Fe3+)(2)(AsO4)(2)(H2O,OH)(2), the Ni-dominant analogue of tsumcorite and cobalttsumcorite, was found in the oxidation zone of a hydrothermal orebody containing gersdorffite and galena at the Km-3 mine, Lavrion, Attiki Prefecture, Greece. It is associated with annabergite, nickellotharmeyerite, nickelaustinite, gaspeite, calcite, dolomite, aragonite, quartz, goethite, cerussite, arseniosiderite, mimetite, oxyplumboromeite and Mn oxides/hydroxides. Nickeltsumcorite occurs as open-work aggregates and interrupted crusts up to 3 mm x 5 mm in area and up to 0.2 mm thick. They typically consist of coarse radial spherulites or dense concentric nodules up to 0.15 mm in diameter. Bunches or hemispherical clusters of crude individuals and separate imperfect, elongated crystals (up to 0.02 mm long) are also observed. Nickeltsumcorite is yellow, brownish-yellow, light brown or brown, with a yellow streak and a vitreous lustre. The Mohs hardness is similar to 4. The mineral is brittle; one direction of distinct cleavage is observed under the microscope. D(calc.) = 5.02 g cm(-3). Nickeltsumcorite is optically biaxial (-), alpha = 1.82(2), beta = 1.87(1), gamma = 1.90(1), 2V(obs.) is large. The chemical composition (wt.%, electron-microprobe data, H2O by difference) is CaO 2.79, PbO 28.12, MgO 0.30, CoO 0.15, NiO 17.39, ZnO 0.76, Mn2O3 0.57, Fe2O3 6.83, As2O5 38.17, H2O 4.92, total 100.00. The empirical formula, calculated based on 10 O apfu, is (Pb0.76Ca0.30)(Sigma 1.06)(Ni1.39Fe0.513+Zn0.06Mn0.043+ Mg0.04Co0.01)(Sigma 2.05)As1.99O7.97[(H2O)(1.25)(OH)(0.78)]. The strongest reflections in the powder X-ray diffraction pattern [d,angstrom(I)(hkl)] are 4: 64(100)((1) over bar 11), 4.47(41)((2) over bar 01), 3.238(82)((1) over bar 12), 3.008(60)(201), 2.859(41)(021), 2.545(79)((3) over bar 12, 112), 2.545(79)((3) over bar 12, 112) and 2.505(61)(220, (2) over bar 03). The cation composition, powder X-ray diffraction data and IR spectrum show that nickeltsumcorite belongs to the tsumcorite structure type. The new mineral is monoclinic, space group C2/m, a = 9.124(8), b = 6.339(3), c = 7.567(7) angstrom, beta = 115.19(6)degrees, V = 396.0(7) angstrom(3) and Z = 2. Nickeltsumcorite forms a solid-solution series with nickellotharmeyerite.

Lead and copper( I) chloride arsenite was found in the ancient metallurgic slag from the Vrissaki area, Lavrion district, Attik Peninsula, Greece. Its chemical composition corresponds to the idealized formula Pb 6 Cu+( AsO 3) 2 Cl 7. The IR spectrum shows the presence of 3 3 AsO - anions and only a trace amount of O- H bonds. The crystal structure was solved by direct methods and refined to R( F) = 0.0304 based on 1778 unique reflections with I > 2s( I). The compound is trigonal ( rhombohedral), R3, a = 9.8691( 2), c = 34.2028( 13), V = 2885.01( 14)3, Z = 6. Two crystallographically nonequivalent As3+ cations occupy apexes of the AsO 3 pyramids. Cu+ cation occupies an apex of the CuCl 3 pyramid. The group [ Cl 3 Cu- AsO 3] is arranged along the c axis. Pb cations occupy two sites with seven- and eight- fold coordination. The crystalchemical formula of the compound is Pb 6 ( Cu+ Cl 3)( As3+ O 3) 2 Cl 4.

A new mineral, hilarionite, ideally Fe 2 3+ (SO4)(AsO4)(OH) · 6H2O, has been found in the Hilarion Mine, Agios Konstantinos, Kamariza, Lavrion district, Attiki Prefecture, Greece. It was formed in the oxidation zone of a sulfide-rich orebody in association with goethite, gypsum, bukovskyite, jarosite, melanterite, chalcanthite, allophane, and azurite. Hilarionite occurs as light green (typically with an olive or grayish tint) to light yellowish green spherulites (up to 1 mm in size) and bunches of prismatic to acicular “individuals” up to 0.5 mm long that are in fact near-parallel or divergent aggregates of very thin, curved fibers up to 0.3 mm long and usually lesser than 2 μm thick. The luster is silky to vitreous. The Mohs’ hardness is ca. 2. Hilarionite is ductile, its “individuals” are flexible and inelastic; fracture is uneven or splintery. D(meas) = 2.40(5), D(calc) = 2.486 g/cm3. IR spectrum shows the presence of arsenate and sulfate groups and H2O molecules in significant amounts. The Mössbauer spectrum indicates the presence of Fe3+ at two six-fold coordinated sites and the absence of Fe2+. Hilarionite is optically biaxial (+), α = 1.575(2), γ = 1.64(2), 2V is large. The chemical composition (electron microprobe, average of 7 point analyses; H2O determined by modified Penfield method) is as follows, wt %: 0.03 MnO, 0.18 CuO, 0.17 ZnO, 33.83 Fe2O3, 0.22 P2O5, 18.92 As2O5, 22.19 SO3, 26.3 H2O, total is 101.82%. The empirical formula calculated on the basis of 15 O is: (Fe 1.90 3+ Cu0.01Zn0.01)Σ1.92[(SO4)1.24(AsO4)0.74(PO4)0.01]Σ1.99(OH)1.01 · 6.03H2O. The X-ray powder diffraction data show close structural relationship of hilarionite and kaňkite, Fe 2 3+ (AsO4)2 · 7H2O. Hilarionite is monoclinic, space group C2/m, Cm or C2, a = 18.53(4), b = 17.43(3), c = 7.56(1) Å, β = 94.06(15)°, V = 2436(3) Å3, Z = 8. The strongest reflections in the X-ray powder diffraction pattern (d, Å-I[hkl]) are: 12.66–100[110], \(7.60 - 6[00\bar 1]\), 5.00–10[22l], \(4.70 - 10[31\bar 1]\), 4.33–7[040]. Hilarionite is named after its type locality.

Transparent prismatic crystals of Pb-2(AsO2OH)Cl-2 were collected in black metallurgical slag on the coast in the Punta Zeza area, 3 km south of the town of Lavrion, Greece. Analyses by energy-dispersive X-ray spectrometry (EDS) provided the following chemical composition: PbO 73.04, As2O3 15.97, Cl 11.42, O=Cl -2.58, total 97.85 wt.%. The empirical formula calculated on the basis of As = 1 is HxPb2.03(AsO3)(1.00)Cl-1.995 (x = 0.96). The infrared spectrum of Pb-2(AsO2OH)Cl-2 has characteristic AsO33- bands at 707 and 594 cm(-1), O-H stretching vibrations at 3310 and 2900 cm(-1) and a band at 1107 cm(-1) which is assigned to As-O-H bending vibrations. The structure, which is monoclinic P2(1)/m, a = 6.4235(8), b = 5.5399(7), c = 9.321(1) angstrom, beta = 90.767(2)degrees, V = 331.67(7) angstrom(3), R-1 = 0.035, is identical to that of synthetic Pb-2(AsO2OH)Cl-2 and contains two symmetrically unique Pb sites and one As site. The crystal structure is based on [Pb2AsO2OH](2+) double chains interconnected via weak Pb-Cl bonds to produce a three-dimensional framework which is closely related to that of Pb oxysalt minerals containing [O2Pb3](2+) chains of oxocentred [OPb4](6+) tetrahedra including mendipite, damaraite, rickturnerite and plumboselite.

The crystal structure of new lead chloride arsenite, Pb-5(As3+O3)Cl-7 [orthorhombic, Pbcn, a = 16.894(2), h = 10.913 (1), c = 16.760(2) angstrom, V = 3090.1(7) angstrom(3)], from the historic slags of Lavrion, Greece, has been solved by direct methods and refined to R-1 = 0.069. The structure contains five symmetrically unique Pb, one As, eight Cl and three O sites. The As atom forms three nearly equal As-O bonds which result in the formation of an AsO3 trigonal pyramid with As at the apex. The Pb1, Pb2, Pb3 and Pb4 atoms are bonded to the AsO3 groups via Pb2+-O bonds to form complex [Pb-4(AsO3)] chains parallel to the b axis. The Pb(5) atom is coordinated solely by Cl- anions. The resulting Pb(5)Cl-7 polyhedra share common edges and corners to produce bent chains parallel to the c axis. A short compilation of structural features of known lead chloride arsenites is given.

Agardite-(Nd), ideally NdCu6(AsO4)(3) (OH)(6)center dot 3H(2)O, has been approved by the IMA Commission on New Minerals, Nomenclature and Classification as a new mineral species, a Nd-dominant analogue of agardite-(Y), -(La) and -(Ce), a member of the mixite group. The material considered as the holotype was found in the Hilarion Mine, Agios Kon-stantinos (Kamariza), Lavrion District, Attiki Prefecture, Greece. Agardite-(Nd) occurs as thin, acicular to hair-like crystals up to 0.5 mm long and up to 5 mu m thick, elongate along [001], with hexagonal cross section. More commonly, agardite-(Nd), agardite-(Y) and/or agardite-(La) form rims (up to 3 mu m thick) of zoned acicular crystals (up to 0.015 x 1.2 mm) with a core consisting of zalesiite. They are usually combined in sprays or radiating clusters up to 2 mm. Gradual compositional transitions among zalesiite, agardite-(Nd), agardite-(Y) and agardite-(La) are typical. The minerals of the agardite- zalesiite solid-solution system are associated here with zincolivenite, azurite, malachite and calcite in cavities of an oxidized ore mainly consisting of goethite and in cracks of supergene altered mica schist. Agardite-(Nd) is transparent, light bluish green, with white streak, and lustre vitreous in crystals and silky in aggregates. Crystals are brittle, cleavage is none observed, and fracture is uneven. Calculated density is 3.81 g/cm(3). Optically, agardite-(Nd) is uniaxial positive, omega = 1.709-1.712, epsilon = 1.775-1.780. Pleochroism is strong: O = pale turquoise-coloured, E = bright green-blue. Chemical composition of agardite-(Nd) (averaged of 6 electron microprobe analyses, H 2 O by difference) is: CuO 42.63, ZnO 3.52, CaO 2.15, Y2O3 1.27, La2O3 2.16, Ce2O3 0.38, Pr2O3 0.79, Nd2O3 3.05, Sm2O3 0.32, Gd2O3 0.40, Dy2O3 0.31, As2O5 33.65, H2Ocalc. 9.37, total 100.00 wt. %. The empirical formula based on 3 As atoms is: [(Nd0.19La0.14Y0.12Pr0.05Gd0.02Ce0.02Sm0.02Dy0.02)(Sigma REE0.58)Ca-0.39](Sigma 0.97)(Cu5.49Zn0.44)(Sigma 5.93) (AsO4)(3)(OH)(5.38)center dot 2.64H(2)O. Chemical data on other minerals of the agardite-zalesiite system from the Hilarion Mine are also given and discussed. Agardite-(Nd) is hexagonal, space group P6(3)/m; unit cell parameters are: a = 13.548(8), c = 5.894(6) angstrom, V = 937(2) angstrom(3), Z = 2. The strongest reflections of the X-ray powder diagram (d,angstrom- I[hkl]) are: 11.70- 100[100]; 4.443- 22[111, 120]; 3.545- 18[211, 121]; 2.935-18[221, 400]; 2.695-13[112, 320, 230], 2.559-10[410], 2.453-30[212, 122, 231]. The type specimen is deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.

Unusual Ti–Cr–Zr-rich garnet crystals from high-temperature melilitic skarn of the Maronia area, western Thrace, Greece, were investigated by electron-microprobe analysis, powder and single-crystal X-ray diffraction, IR, Raman and Mössbauer spectroscopy. Chemical data showed that the garnets contain up to 8 wt.% TiO2, 8 wt.% Cr2O3 and 4 wt.% ZrO2, representing a solid solution of andradite (Ca3Fe3+ 2Si3O12 ≈46 mol%), uvarovite (Ca3Cr2Si3O12 ≈23 mol%), grossular (Ca3Al2Si3O12 ≈10 mol%), schorlomite (Ca3Ti2[Si,(Fe3+,Al3+)2]O12 ≈15 mol%), and kimzeyite (Ca3Zr2[Si,Al2]3O12 ≈6 mol%). The Mössbauer analysis showed that the total Fe is ferric, preferentially located at the octahedral site and to a smaller extent at the tetrahedral site. Single-crystal XRD analysis, Raman and IR spectroscopy verified substitution of Si mainly by Al3+, Fe3+ and Ti4+. Cr3+ and Zr4+ are found at the octahedral site along with Fe3+, Al3+ and Ti4+. The measured H2O content is 0.20 wt.%. The analytical data suggest that the structural formula of the Maronia garnet can be given as: (Ca2.99Mg0.03)Σ=3.02(Fe3+ 0.67Cr0.54Al0.33Ti0.29Zr0.15)Σ=1.98(Si2.42Ti0.24Fe0.18Al0.14)Σ=2.98O12OH0.11. Ti-rich garnets are not common and their crystal chemistry is still under investigation. The present work presents new evidence that will enable the elucidation of the structural chemistry of Ti- and Cr-rich garnets.