MINERAIS RECENTEMENTE DESCRITOS NO BRASIL: A PARTICIPAÇÃO DO CENTRO DE PESQUISA PROF. MANOEL TEIXEIRA DA COSTA - CPMTC, INSTITUTO DE GEOCIÊNCIAS (UFMG)

Embora o potencial mineral do Brasil seja imenso e, por conseguinte, a possibilidade de encontro de novas espécies minerais nos empreendimentos minerários seja naturalmente alta, até 2010 somente 51 descobertas haviam sido verificadas no país. Entretanto, nos últimos sete anos, através de um projeto de Tese de Doutoramento realizado no Programa de Pós-Graduação em Geologia do IGC/UFMG, esta situação procurou ser mudada. Com ênfase em dois dos principais ambientes geológicos do Estado de Minas Gerais e adjacências, a Província Pegmatítica Oriental do Brasil e a Serra do Espinhaço, estudos foram conduzidos visando especificamente o encontro de novos minerais. Destacam-se os resultados extremamenete satisfatórios; nesses anos foram descobertos oito minerais, o que representa média de 1,3 mineral/ano, contrastando com os inexpressivos 0,2 mineral/ano verificados desde 1789 (ano em que o crisoberilo foi descrito). Os novos minerais são, incluindo seus códigos de identificação na International Mineralogical Association (IMA): carlosbarbosaíta [(UO2)2Nb2O6(OH)2.2H2O], IMA 2010-047; pauloabibita [NaNbO3], IMA 2012-090; cesarferreiraíta [Fe2+Fe3+2(AsO4)2(OH)2.8H2O], IMA 2012-099; correianevesita [Fe2+Mn2+2(PO4)2.3H2O], IMA 2013-007; almeidaíta [Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2], IMA 2013-020; wilancookita [(Ba,K,Na)8(Ba,Li,[])6Be24P24O96.3H2O], IMA 2015-034; parisita-(La) [CaLa2(CO3)3F2], IMA 2016-031; e brandãoita [BeAl2(PO4)2(OH)2(H2O)4], IMA 2016-071a. Este foi o primeiro programa de pesquisa desenvolvido no país voltado especialmente para a descoberta de novos minerais, tendo alcançado pleno êxito.Palavras Chave: Novos minerais, Centro de Pesquisa Prof. Manoel Teixeira da Costa, (IGC-UFMG), BrasilAbstract:RECENT MINERALS DESCRIBED IN BRAZIL: PARTICIPATION OF THE CENTRO DE PESQUISA PROF. MANOEL TEIXEIRA DA COSTA - CPMTC, GEOSCIENCES INSTITUTE (UFMG). Although the mineral potential of Brazil is immense and, consequently, the possibility of finding new mineral species in mining projects is obviously high, until 2010 only 51 discoveries had been verified in this country. However, in the last seven years, through a PhD Thesis project carried at the Postgraduate in Geology Program of the IGC/UFMG, this situation has been modified. With emphasis on two of the main geological environments of Minas Gerais State and surrounding regions, the Eastern Brazil Pegmatite Province and the Espinhaço Mountain Range, studies were conducted specifically aimed at finding new minerals. The results are extremely satisfactory; in those years eight minerals were discovered, representing an average of 1.3 mineral/year, contrasting with the inexpressive 0.2 mineral/year verified since 1789 (year of chrysoberyl description). The new minerals are, including their identification codes in the International Mineralogical Association (IMA): carlosbarbosaite [(UO2)2Nb2O6(OH)2.2H2O], IMA 2010-047; pauloabibite [NaNbO3], IMA 2012-090; cesarferreiraita [Fe2+Fe3+2(AsO4)2(OH)2.8H2O], IMA 2012-099; correianevesite [Fe2+Mn2+2(PO4)2.3H2O], IMA 2013-007; almeidaite [Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2], IMA 2013-020; wilancookite [(Ba,K,Na)8(Ba,Li,[])6Be24P24O96.3H2O], IMA 2015-034; parisite-(La) [CaLa2(CO3)3F2], IMA 2016-031; and brandãoite [BeAl2(PO4)2(OH)2(H2O)4], IMA 2016-071a. This was the first research program developed in the country focused especially on the discovery of new minerals, reaching full success.Keywords: New minerals, Prof. Manoel Teixeira da Costa Research Center (IGC-UFMG), Brazil.

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A comment on “An evolutionary system of mineralogy: Proposal for a classification of planetary materials based on natural kind clustering”

American Mineralogist ◽

10.2138/am-2021-7590 ◽

2021 ◽

Vol 106 (1) ◽

pp. 150-153

Author(s):

Frédéric Hatert ◽

Stuart J. Mills ◽

Frank C. Hawthorne ◽

Mike S. Rumsey

Keyword(s):

Mineral Species ◽

New Mineral ◽

Evolutionary System ◽

Species Classification ◽

Classification Schemes ◽

International Mineralogical Association ◽

Mineralogical Association ◽

New Mineral Species ◽

Planetary Materials

Abstract The classification and nomenclature of mineral species is regulated by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMACNMNC). This mineral species classification is necessary for Earth Sciences, as minerals constitute most planetary and interstellar materials. Hazen (2019) has proposed a classification of minerals and other Earth and planetary materials according to “natural clustering.” Although this classification is complementary to the IMA-CNMNC mineral classification and is described as such, there are some unjustified criticisms and factual errors in the comparison of the two schemes. It is the intent of the present comment to (1) clarify the use of classification schemes for Earth and planetary materials, and (2) counter erroneous criticisms or statements about the current IMA-CNMNC system of approving proposals for new mineral species and classifications.

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The discovery of new mineral species and type minerals from Brazil

Brazilian Journal of Geology ◽

10.1590/23174889201500010011 ◽

2015 ◽

Vol 45 (1) ◽

pp. 143-158 ◽

Cited By ~ 2

Author(s):

Daniel Atencio

Keyword(s):

Iron Ore ◽

18Th Century ◽

Mineral Species ◽

New Mineral ◽

Synthetic Analogue ◽

Copper Ore ◽

International Mineralogical Association ◽

Mineralogical Association ◽

New Mineral Species ◽

Wide Range

Minerals were seen merely as sources of chemicals: iron ore, copper ore, etc. However, minerals are not just chemicals associations, since they display crystal structures. These two features together provide properties that can be technologically useful. Even though a mineral occurs in very small amount, which does not allow its extraction, it can serve as a model for obtaining the synthetic analogue on an industrial scale. It is necessary that a new-mineral proposal be submitted for approval by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA) before publication. Only 65 valid mineral species were first described from Brazil, that is, the type minerals from Brazil. Nineteen of these were published between 1789 and 1959 (0.11 per year). From 1959, when the CNMMN (today CNMNC) - IMA was established, to 2000, 18 approved Brazilian mineral species remain valid (0.43 per year). However, the number of type minerals from Brazil approved in the last 15 years (2000 to 2014) was substantially increased: 28 (1.87 per year). This number is very small considering the wide range of Brazilian geological environments. The two first type species from Brazil, discovered in the 18th century, chrysoberyl and euclase, are important gemological minerals. Two other gem minerals, tourmaline-supergroup members, were published only in the 21st century: uvite and fluor-elbaite. Some type minerals from Brazil are very important technologically speaking. Some examples are menezesite, coutinhoite, lindbergite, pauloabibite, and waimirite-(Y).

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The tadpole of the hylodid frog Hylodes charadranaetes Heyer and Cocroft, 1986

Zootaxa ◽

10.11646/zootaxa.2680.1.6 ◽

2010 ◽

Vol 2680 (1) ◽

pp. 65

Author(s):

PAULO NOGUEIRA COSTA ◽

CARLA COSTA SIQUEIRA ◽

DAVOR VRCIBRADIC ◽

LUIZ NORBERTO WEBER ◽

CARLOS FREDERICO D. ROCHA

Keyword(s):

Rio Grande ◽

Species Group ◽

Minas Gerais ◽

Riparian Forests ◽

Atlantic Rainforest ◽

Rio Grande Do Sul ◽

Campos Rupestres ◽

Eastern Brazil ◽

Minas Gerais State ◽

Species Groups

The genus Hylodes Fitzinger, 1826 is restricted to eastern Brazil, occurring from the states of Espírito Santo to Rio Grande do Sul (Lingnau et al. 2008, Frost 2010). Except for Hylodes otavioi, which inhabits riparian forests in rocky fields (“campos rupestres”) habitats within the Cerrado domain in Minas Gerais State (Sazima & Bokermann 1982), all other species in the genus are endemic to the Atlantic Rainforest domain (Lingnau et al. 2008). The genus currently comprises 24 species (Frost 2010) of small to medium-sized diurnal frogs that live associated to lotic streams in forests (e.g. Lingnau et al. 2008; Silva & Benmaman 2008). Heyer (1982) proposed four species groups for Hylodes, which are still recognized today (but see Haddad et al. 1996; Canedo & Pombal 2007): the glaber (formerly pulcher), lateristrigatus, mertensi, and nasus species groups. The Hylodes lateristrigatus species group is the most specious, being currently composed by 18 species: H. amnicola Pombal, Feio, and Haddad, 2002, H. babax Heyer, 1982, H. charadranaetes Heyer and Cocroft, 1986, H. fredi Canedo and Pombal, 2007, H. heyeri Haddad, Pombal, and Bastos, 1996, H. lateristrigatus (Baumann, 1912), H. magalhaesi (Bokermann, 1964), H. meridionalis (Mertens, 1927), H. ornatus (Bokermann, 1967), H. otavioi Sazima and Bokermann, 1983, H. perere Silva & Benmaman, 2008, H. perplicatus (Miranda-Ribeiro, 1926), H. pipilans Canedo and Pombal, 2007, H. phyllodes Heyer and Cocroft, 1986, H. regius Gouvêa, 1979, H. sazimai Haddad and Pombal, 1995, H. uai Nascimento, Pombal, and Haddad, 2001, and H. vanzolinii Heyer, 1982 (Silva & Benmaman 2008; Frost 2010).

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Fluorlamprophyllite, Na3(SrNa)Ti3(Si2O7)2O2F2, a new mineral from Poços de Caldas alkaline massif, Morro do Serrote, Minas Gerais, Brazil

Mineralogical Magazine ◽

10.1180/minmag.2017.081.027 ◽

2018 ◽

Vol 82 (1) ◽

pp. 121-131 ◽

Cited By ~ 5

Author(s):

Marcelo B. Andrade ◽

Hexiong Yang ◽

Robert T. Downs ◽

Gunnar Färber ◽

Reynaldo R. Contreira Filho ◽

...

Keyword(s):

Layered Silicate ◽

Minas Gerais ◽

New Mineral ◽

Chemical Formula ◽

Calculated Density ◽

Cell Parameters ◽

New Mineral Species ◽

Poços De Caldas ◽

Mohs Hardness ◽

Alkaline Massif

ABSTRACTA new mineral species, fluorlamprophyllite (IMA2013-102), ideally Na3(SrNa)Ti3(Si2O7)2O2F2, has been found in the Poços de Caldas alkaline massif, Morro do Serrote, Minas Gerais, Brazil. Alternatively, the idealized chemical formula could be written as (SrNa)[(Na3Ti)F2][Ti2(Si2O7)2O2], setting the large interlayer cations before the cations of the layer. Fluorlamprophyllite is the F-analogue of lamprophyllite. It is associated with aegirine, analcime, natrolite, nepheline and microcline. Fluorlamprophyllite crystals are brownish-orange and bladed. The mineral is transparent with a pale yellow streak and an adamantine lustre. It is brittle and has a Mohs hardness of ~3; cleavage is perfect on {100} and no parting was observed. The calculated density is 3.484 g/cm3. Optically, fluorlamprophyllite is biaxial (+), with α = 1.735(7), β = 1.749(7) and γ = 1.775(9) and 2Vmeas = 72(3)°. An electron microprobe analysis produced an average composition (wt.%) (9 points) of Na2O 10.63(30), K2O 0.47(3), SiO2 30.51(13), SrO 18.30(24), MgO 0.81(17), Al2O3 0.23(2), CaO 1.11(7), MnO 5.03(38), TiO2 27.41(87), Fe2O3 2.45(37), F 2.86(23), plus H2O 1.00 (added to bring the total close to 100%), –O = F –1.20, with the total = 98.61%. The elements Nb and Ba were sought, but contents were below microprobe detection limits. The resultant chemical formula was calculated on the basis of 18 (O + F) atoms per formula unit. The addition of 1.00 wt.% H2O brought [F+(OH)] = 2 pfu, yielding (Na2.63Sr1.35Mn0.54Ca0.15Mg0.15K0.08)Σ4.90(Ti2.63Fe0.24Al0.04)Σ2.91Si3.89O16[F1.15(OH)0.85]Σ2.00. The mineral is monoclinic, with space group C2/m and unit-cell parameters a = 19.255(2), b = 7.0715(7), c = 5.3807(6) Å, β = 96.794(2)° and V = 727.5(1) Å3. The structure is a layered silicate inasmuch as the O atoms are arranged in well-defined, though not necessarily close-packed layers.

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Threatened endemic species of Hibiscus l. (Malvaceae) in Minas Gerais, Brazil

Environmental Scientiae ◽

10.6008/cbpc2674-6492.2019.001.0002 ◽

2019 ◽

Vol 1 (1) ◽

pp. 9-15

Author(s):

Luccas Henrique Gomes Rigueiral ◽

Victor Martins Gonçalez ◽

Marília Cristina Duarte ◽

Cleber Vinicius Vitorio da Silva ◽

Rafael Tavares ◽

...

Keyword(s):

Endemic Species ◽

Native Species ◽

Minas Gerais ◽

Critically Endangered ◽

Atlantic Rainforest ◽

Mountain Range ◽

Isolated Populations ◽

Southeast Brazil ◽

Staminal Tube ◽

Minas Gerais State

Hibiscus L. is one of the largest genera of Malvaceae, Southeast Brazil has six endemic species of 14 native species, mainly distributed in cerrado. These Hibiscus are hairy shrubs, with showy flowers of pink corolla, dark base, 5-toothed staminal tube apex, loculicidal capsule of 5 cells. The species inhabit wet ecosystems of the atlantic rainforest and cerrado. After the last study of Hibiscus taxonomy evidencing four endemic species from Minas Gerais state, showed to have the largest endemism center of Hibiscus in Brazil, therefore, using IUCN classification methodology, we indicated H. hilarianus and H. multiformis as vulnerable, H. itirapinensis as endangered and H. mariae as critically endangered. The species are represented by small isolated populations distributed at the mountains and plateaus between Espinhaço mountain range and Planalto Paulista, considered a region with great endemic biodiversity. According to the previously analysis, it is recommended specific studies with techniques and appropriate methodology to research the development and evolutionary characteristics of hibiscus species in Minas Gerais state.

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Redefinition of thérèsemagnanite, NaCo4(SO4)(OH)6Cl·6H2O: new data and relationship to ‘cobaltogordaite’

Mineralogical Magazine ◽

10.1180/minmag.2017.081.030 ◽

2018 ◽

Vol 82 (1) ◽

pp. 159-170 ◽

Cited By ~ 2

Author(s):

Anatoly V. Kasatkin ◽

Jakub Plášil ◽

Radek Škoda ◽

Dmitriy I. Belakovskiy ◽

Joe Marty ◽

...

Keyword(s):

Crystal Structure Data ◽

New Mineral ◽

X Ray Diffraction ◽

Oh Groups ◽

X Ray ◽

International Mineralogical Association ◽

Mineralogical Association ◽

Holotype Specimen ◽

Cl Atoms ◽

The Ideal

ABSTRACTThérèsemagnanite was originally described from the Cap Garonne mine, Var, France. Its ideal formula was reported as (Co,Zn,Ni)6(SO4)(OH,Cl)10·8H2O; without crystal structure data, only the powder X-ray diffraction pattern was given. Revision of the holotype material revealed that thérèsemagnanite is identical to ‘cobaltogordaite’ (IMA2014-043), recently described from the Blue Lizard mine, Utah, USA. Thérèsemagnanite is thus redefined in accordance with the new data obtained for the neotype specimen from Blue Lizard (formerly the holotype specimen of ‘cobaltogordaite’) and ‘cobaltogordaite’ has been discredited by the International Mineralogical Association Commission on New Mineral Nomenclature and Classification (IMA CNMNC). Thérèsemagnanite has the ideal, end-member formula NaCo4(SO4)(OH)6Cl·6H2O. The empirical formulae of the holotype (Cap Garonne) and the neotype (Blue Lizard), both based on microprobe analyses and calculated on the basis of 17 O + Cl atoms per formula unit (with fixed 6 OH groups and 6 H2O molecules; H content is calculated by stoichiometry) are (Na0.64K0.09)Σ0.73(Co2.35Zn1.22Ni0.50)Σ4.07S1.02O3.98(OH)6Cl1.02·6H2O and Na1.01(Co1.90Zn1.37Ni0.48Cu0.15Mn0.05)Σ3.95S1.03O4.09(OH)6Cl0.91·6H2O, respectively. Thérèsemagnanite is trigonal,P$\overline 3 $,a= 8.349(3),c= 13.031(2) Å,V= 786.6(4) Å3and Z = 2 (neotype). The strongest powder X-ray diffraction lines are [dobsin Å (hkl) (Irel)]: 13.10 (001)(100), 6.53 (002)(8), 4.173 (110)(4), 3.517 (112)(5), 2.975 (104, 10$\overline 4 $)(4), 2.676 (211)(5) and 2.520 (12$\bar 2$)(5) (neotype). Thérèsemagnanite is a cobalt analogue of gordaite, NaZn4(SO4)(OH)6Cl·6H2O. These minerals represent the gordaite group, accepted by the IMA CNMNC.

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The mineral marrucciite: monoclinic Hg3Pb16Sb18S46

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536806040980 ◽

2007 ◽

Vol 63 (11) ◽

pp. i190-i190 ◽

Cited By ~ 5

Author(s):

František Laufek ◽

Jiří Sejkora ◽

Karla Fejfarová ◽

Michal Dušek ◽

Daniel Ozdín

Keyword(s):

Crystal Structure ◽

Slovak Republic ◽

Precise Determination ◽

New Mineral ◽

Mountain Range ◽

New Mineral Species ◽

Apuan Alps ◽

New Discovery ◽

Ore District

Recently, a new mineral species, monoclinic marrucciite, mercury lead antimony sulfide, Hg3Pb16Sb18S46 [Orlandi et al. (2007). Eur. J. Mineral. 19, 267–279], was discovered in the Fe—Ba deposit of Buca della Vena, Apuan Alps (Italy). In that report, the crystal structure was refined to R = 0.096. Our new discovery of crystals of this sulfosalt in the Gelnica ore district, situated in the Spišsko-gemerské rudohorie mountain range, Slovak Republic, has now allowed a substantially more precise determination of the crystal structure (R = 0.024). The monoclinic unit cell contains 19 independent cation positions (including two mixed SbIII/PbII positions) and 23 independent S positions.

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Micromorphological features revealing two new species of Portulaca (Portulacaceae) from Brazil, segregated from P. hirsutissima

Phytotaxa ◽

10.11646/phytotaxa.270.2.3 ◽

2016 ◽

Vol 270 (2) ◽

pp. 103 ◽

Cited By ~ 1

Author(s):

THAÍLA VIEIRA A. SANTOS ◽

ALEXA ARAÚJO DE O. PAES COELHO ◽

MARCOS DA COSTA DÓREA ◽

FRANCISCO DE ASSIS R. DOS SANTOS ◽

KELLY REGINA B. LEITE ◽

...

Keyword(s):

New Species ◽

Distribution Pattern ◽

Rio De Janeiro ◽

Pollen Grains ◽

Minas Gerais ◽

Central Brazil ◽

Eastern Brazil ◽

Minas Gerais State ◽

Two New Species ◽

Rocky Soil

Portulaca hirsutissima (Portulacaceae) is a succulent herb occurring in open fields, sandy or rocky soil of separate Brazilian areas. On the basis of the analyses of seeds and pollen grains macro- and micromorphology, a significative variation, which is related to the distribution pattern, was found. Two new species are here proposed, described and illustrated. Portulaca giuliettiae sp. nov. occurs in Eastern Brazil, from Paraiba to Rio de Janeiro and P. goiasensis sp. nov. is restricted to the Chapada dos Veadeiros, in Central Brazil. P. hirsutissima is now to be considered as a restricted species from Minas Gerais State. A lectotype for the name P. hirsutissima is designated from a specimen preserved at P.

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Lucchesiite, CaFe2+3Al6(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup

Mineralogical Magazine ◽

10.1180/minmag.2016.080.067 ◽

2017 ◽

Vol 81 (1) ◽

pp. 1-14 ◽

Cited By ~ 12

Author(s):

Ferdinando Bosi ◽

Henrik Skogby ◽

Marco E. Ciriotti ◽

Petr Gadas ◽

Milan Novák ◽

...

Keyword(s):

Czech Republic ◽

Sri Lanka ◽

Polarized Light ◽

New Mineral ◽

Crystal Chemical Analysis ◽

Calculated Density ◽

International Mineralogical Association ◽

Conchoidal Fracture ◽

New Mineral Species ◽

Coupled Substitution

AbstractLucchesiite, CaFe32+Al6(Si6O18)(BO3)3(OH)3O, is a new mineral of the tourmaline supergroup. It occurs in the Ratnapura District, Sri Lanka (6°35'N, 80°35'E), most probably from pegmatites and in Mirošov near Strážek, western Moravia, Czech Republic, (49°27'49.38"N, 16°9'54.34"E) in anatectic pegmatite contaminated by host calc-silicate rock. Crystals are black with a vitreous lustre, conchoidal fracture and grey streak. Lucchesiite has a Mohs hardnessof ∼7 and a calculated density of 3.209 g/cm3(Sri Lanka) to 3.243 g/cm3(Czech Republic). In plane-polarized light, lucchesiite is pleochroic (O = very dark brown and E = light brown) and uniaxial (–). Lucchesiite is rhombohedral, space groupR3m,a≈ 16.00 Å,c≈ 7.21 Å,V≈ 1599.9 Å3,Z= 3. The crystal structure of lucchesiite was refined toR1 ≈ 1.5% using ∼2000 unique reflections collected with MoKα X-ray intensity data. Crystal-chemical analysis for the Sri Lanka (holotype) and Czech Republic (cotype) samples resulted in the empirical formulae, respectively:X(Ca0.69Na0.30K0.02)∑1.01Y(Fe1.442+Mg0.72Al0.48Ti0.334+V0.023+Mn0.013+Zn0.01)∑3.00Z(Al4.74Mg1.01Fe0.253+)∑6.00[T(Si5.85Al0.15)∑6.00O18](BO3)3V(OH)3W[O0.69F0.24(OH)0.07]∑1.00andX(Ca0.49Na0.45□0.05K0.01)∑1.00Y(Fe1.142+Fe0.953+Mg0.42Al0.37Mn0.03Ti0.084+Zn0.01)∑3.00Z(Al5.11Fe0.383+Mg0.52)∑6.00[T(Si5.88Al0.12)∑6.00O18](BO3)3V[(OH)2.66O0.34]∑3.00W(O0.94F0.06)∑1.00.Lucchesiite is an oxy-species belonging to the calcic group of the tourmaline supergroup. The closest end-member composition of a valid tourmaline species is that of feruvite, to which lucchesiite is ideally related by the heterovalent coupled substitutionZAl3++O1O2–↔ZMg2++O1(OH)1–. The new mineral was approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA 2015-043).

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Tl-bearing sulfosalt from the Lengenbach quarry, Binn Valley, Switzerland: Philrothite, TlAs3S5

Mineralogical Magazine ◽

10.1180/minmag.2014.078.1.01 ◽

2014 ◽

Vol 78 (1) ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

L. Bindi ◽

F. Nestola ◽

E. Makovicky ◽

A. Guastoni ◽

L. De Battisti

Keyword(s):

Crystal Structure ◽

Powder Diffraction ◽

Double Layers ◽

New Mineral ◽

Monoclinic Space Group ◽

Electron Pairs ◽

International Mineralogical Association ◽

Mineralogical Association ◽

Reflected Light ◽

Mohs Hardness

AbstractPhilrothite, ideally TlAs3S5, is a new mineral from the Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs as very rare crystals up to 200 mm across on realgar associated with smithite, rutile and sartorite. Philrothite is opaque with a metallic lustre and shows a dark brown streak. It is brittle; the Vickers hardness (VHN25) is 128 kg/mm2 (range: 120–137) (Mohs hardness of 3–3½). In reflected light philrothite is moderately bireflectant and weakly pleochroic from dark grey to light grey. Under crossed polars it is anisotropic with grey to bluish rotation tints. Internal reflections are absent. Reflectance percentages for the four COM wavelengths (Rmin and Rmax) are: 26.5, 28.8 (471.1 nm), 25.4, 27.2 (548.3 nm), 24.6, 26.3 (586.6 nm) and 24.0, 25.1 (652.3 nm), respectively.Philrothite is monoclinic, space group P21/c, with a = 8.013(2), b = 24.829(4), c = 11.762(3) Å, β = 132.84(2)°, V = 1715.9(7) Å3, Z = 8. It represents the N = 4 homologue of the sartorite homologous series. In the crystal structure [R1 = 0.098 for 1217 reflections with I > 2σ(I)], Tl assumes tricapped prismatic sites alternating to form columns perpendicular to the b axis. Between the zigzag walls of Tl coordination prisms, coordination pyramids of As(Sb) form diagonally-oriented double layers separated by broader interspaces which house the lone electron pairs of these elements.The eight strongest calculated powder-diffraction lines [d in Å(I/I0) (hkl)] are: 12.4145 (52) (020); 3.6768 (100) (61); 3.4535 (45) (131); 3.0150 (46) (53); 2.8941 (52) (81); 2.7685 (76) (230); 2.7642 (77) (34); 2.3239 (52) (092). A mean of five electron microprobe analyses gave Tl 26.28(12), Pb 6.69(8), Ag 2.50(4), Cu 0.04(2), Hg 0.07(2), As 32.50(13), Sb 3.15(3), S 26.35(10), total 97.58 wt.%, corresponding, on the basis of a total of nine atoms, to (Tl0.789Pb0.198)∑=0.987 (As2.662Sb0.159Ag0.142Cu0.004Hg0.002)∑=2.969S5.044. The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (2013-066) and named for Philippe Roth (b. 1963), geophysicist and well known mineral expert on the Lengenbach minerals for more than 25 years.

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