George R Rossman

• PhD
• Professor at California Institute of Technology

Rotherkopfite, KNa2(Fe2.52+Ti1.54+)Fe2+(Si4O12)2, is a new member of the neptunite group, from Rother Kopf, Roth, near Gerolstein, Eifel volcanic fields, Rhineland-Palatinate, Germany. It is found in cavities in a quartz–sanidine xenolith embedded in a vesicular alkaline basalt and is associated with fluorophlogopite and an amphibole supergroup min...

In advanced photonics, there is a growing interest in piezochromic luminescent materials that exhibit multicolor switching, driven by their potential applications in optical recording, memory, and sensors. Here, the piezochromic behavior of 2,4,6‐triphenylpyrylium tetrachloroferrate (Py‐FeCl4) under high pressures from 0 to 9 GPa is reported. The o...

Single-crystal optical spectra of corundum (Al2O3) and the Al2SiO5 polymorphs andalusite, kyanite, and sillimanite, containing both Fe2+ – Fe3+ and Fe2+ – Ti4+ intervalence charge transfer (IVCT) absorption bands were measured at temperatures up to 1000 °C. Upon heating, thermally equilibrated IVCT bands significantly decreased in intensity and rec...

Aluminosilicate garnet is an excellent phase to research solid-solution behavior in silicates. Natural almandine-pyrope, {Fe2+3x,Mg3-3x}[Al2](Si3)O12, and almandine-spessartine, {Fe2+3x,Mn2+3-3x}[Al2](Si3)O12, crystals were measured by UV/Vis/NIR (~29000 to 10000 cm-1) optical absorption spectroscopy using a microscope. The spectra and changes in e...

A natural grossular garnet was found to have a luminescence spectrum with a narrow vibrational structure and short decay time that is unusual for minerals. We propose that such emission is generated by Mn²⁺ accompanied by defect F-centers which both enhance the transition probability and give rise to sensitivity to optical bleaching and reconstitut...

Tiny precious opals, usually not more than one quarter inch in diameter, are abundant in siliceous nodules from certain parts of the ancient Lake Tecopa sediments. This occurrence must have been known to some local collectors since at least as early as 1885. At that time the Harmony Borax Works owned by Coleman and Company operated in Death Valley...

A new mineral of the beryl group, johnkoivulaite, Cs(Be2B)Mg2Si6O18, was recovered from the gem gravels of the Pein Pyit area of the Mogok region in Myanmar. Thus far, only a single crystal has been identified. It has dimensions about 5.8×5.7×5.5 mm. This specimen has an irregular shape but still has discernible crystal form with geometric growth p...

The nominally anhydrous, calcium-silicate garnets, grossular - Ca3Al2Si3O12, andradite - Ca3Fe3+2Si3O12 and their solid solutions Ca3(Alx,Fe3+1-x)2Si3O12, can incorporate various amounts of structural OH-. This has important mineralogical, petrological, and geochemical consequences and extensive experimental investigations have focused on the natur...

Native tungsten (IMA2011-004), W, is officially described as a new mineral from gold placers in the Bol'shaya Pol'ya river valley, Prepolar Urals, Russia, associated with yttriaite-(Y) and from quartz veins in the Mt Neroyka rock-crystal field, Ust–Puiva, Tyumenskaya Oblast', Russia. Tungsten forms polycrystalline grains and masses, and rarely cubo...

Native tungsten (IMA2011-004), W, is officially described as a new mineral from gold placers in the Bol'shaya Pol'ya river valley, Prepolar Urals, Russia, associated with yttriaite-(Y) and from quartz veins in the Mt Neroyka rock-crystal field, Ust–Puiva, Tyumenskaya Oblast', Russia. Tungsten forms polycrystalline grains and masses, and rarely cubo...

Black phosphorus (BP) offers considerable promise for infrared and visible photonics. Efficient tuning of the bandgap and higher subbands in BP by modulation of the Fermi level or application of vertical electric fields has been previously demonstrated, allowing electrical control of its above bandgap optical properties. Here, we report modulation...

Natural radiation-induced red fluorescence of fluorite consists of two broad bands at 750 and 635 nm with very short decay times of 20.3 and less than 5 ns, respectively. The first one is connected to an M center compensated by Na, while the second is connected to an M⁺ center, possibly formed as result of the M center’s destruction by UV irradiati...

Black phosphorus (BP) offers considerable promise for infrared and visible photonics. Efficient tuning of the bandgap and higher subbands in BP by modulation of the Fermi level or application of vertical electric fields has been previously demonstrated, allowing electrical control of its above bandgap optical properties. Here, we report modulation...

Hagstromite, Pb 8 Cu ²⁺ (Te ⁶⁺ O 6 ) 2 (CO 3 )Cl 4 , (IMA2019-093) is a new tellurate mineral from Otto Mountain near Baker, California, USA. It occurs on quartz in association with cerussite, fuettererite and thorneite. It is a secondary oxidation zone mineral and is presumed to have formed by oxidation of earlier formed tellurides, chalcopyrite a...

Northstarite, Pb 6 (Te 4þ O 3) 5 (S 2 O 3), is a new mineral from the North Star mine, Tintic district, Juab County, Utah, USA. It is an oxidation-zone mineral occuring in a vug in massive quartz-baryte-enargite-pyrite in association with anglesite, azurite, chrysocolla, fluorapatite, plumbogummite, tellurite, zincospiroffite, and the new mineral a...

The characteristic red color of many natural tourmalines is due to the presence of Mn(III) cations substituting for aluminum and lithium. These sites originate as Mn(II) and are oxidized by natural γ-irradiation over geologic time as they sit in the Earth's crust. Presented here is a thorough analysis of the spin-allowed and spin-forbidden transiti...

The supracrustal metamorphic rocks of the Dora-Maira Massif, western Alps, have been intensively studied. Certain ultra-high-pressure lithologies contain coesite and nearly end-member composition pyrope, Mg3Al2Si3O12, making this locality petrologically and mineralogically unique. Structural OH-, loosely termed “water”, in pyrope crystals of differ...

Electron probe microanalyser measurements of trace elements with high accuracy are challenging. Accurate Al measurements in olivine are required to calibrate SIMS implant reference materials for measurement of Al in the solar wind. We adopt a combined EPMA/SIMS approach that is useful for producing SIMS reference materials as well as for EPMA at th...

Plasma enhanced chemical vapor deposition (PECVD) techniques have been shown to be an efficient method to achieve single-step synthesis of high-quality monolayer graphene (MLG) without the need of active heating. Here we report PECVD-growth of single-crystalline hexagonal bilayer graphene (BLG) flakes and mm-size BLG films with the interlayer twist...

Warkite (IMA 2013-129) is a new Sc-rich ultrarefractory mineral in the rhönite group of the sapphirine supergroup. It has a P1¯ aenigmatite-type structure with a = 10.367 Å, b = 10.756 Å, c = 8.895 Å, α = 106°, β = 96°, γ = 125°, and Z = 2, and general formula of Ca2(Sc,Ti,Al,Mg,Zr)6Al6O20. Warkite occurs as micrometer-sized crystals in eleven ultr...

Adanite, Pb2(Te4+O3)(SO4), is a new oxidation-zone mineral from the North Star mine, Tintic district, Juab County, Utah, and from Tombstone, Cochise County, Arizona, USA. The characterization of the species is based principally on North-Star holotype material. Crystals are beige wedge-shaped blades, up to about 1 mm in length, in cockscomb intergro...

The calcium-silicate garnets, grossular (Ca₃Al₂Si₃O₁₂), andradite (Ca₃Fe³⁺₂Si₃O₁₂), and their solid solutions [Ca₃(Al_x,Fe³⁺_(1−x)₂Si₃O₁₂], can incorporate various amounts of structural OH–. This has important mineralogical, petrological, rheological, and geochemical consequences and extensive experimental investigations have focused on the nature...

The nominally anhydrous, calcium-silicate garnets, grossular -(Ca3Al2Si3O12), andradite - Ca3Fe3+2Si3O12, schorlomite - Ca3Ti4+2(Si,Fe3+2)O12, and their solid solutions can incorporate structural OH-, often termed "water." The IR single-crystal spectra of several calcium silicate garnets were recorded between 3000 and 4000 cm-1. Spectroscopic resul...

Ethiopia, traditionally known for opal, has become an important source for emerald and sapphire. After these significant discoveries, a new type of Cu-bearing sunstone feldspar, first shown in 2015 to Tewodros Sintayehu (Orbit Ethiopia Plc.), was discovered in the Afar region (L. Kiefert et al., “Sunstone labradorite-bytownite from Ethiopia,” Journ...

Geodes from the El Choique mine in Argentina first appeared on the market in 2017 at a gem fair held in Brazil. The geodes are lined with various minerals, most notably pink amethyst crystals-a new color variety of quartz. The substantial reserves remaining should continue to yield attractive specimens for years to come.

Machiite (IMA 2016-067), Al2Ti3O9, is a new mineral that occurs as a single euhedral crystal, 4.4 μm in size, in contact with an euhedral corundum grain, 12 μm in size, in a matrix of the Murchison CM2 carbonaceous chondrite. The mean chemical composition of holotype machiite by electron probe microanalysis is (wt%) TiO2 59.75, Al2O3 15.97, Sc2O3 1...

Davidbrownite-(NH₄), (NH₄,K)₅ (V⁴⁺O)₂(C₂O₄)[PO_(2.75)(OH)_(1.25)]₄·3H₂O, is a new mineral species from the Rowley mine, Maricopa County, Arizona, USA. It occurs in an unusual bat-guano-related, post-mining assemblage of phases that include a variety of vanadates, phosphates, oxalates and chlorides, some containing NH⁴⁺. Other secondary minerals fou...

Remote Compositional Analysis - edited by Janice L. Bishop November 2019

Cambridge Core - History of Astronomy and Cosmology - Remote Compositional Analysis - edited by Janice L. Bishop

Plasma enhanced chemical vapor deposition (PECVD) techniques have been shown to be an efficient method to achieve single-step synthesis of high-quality monolayer graphene (MLG) without the need of active heating. Here we report PECVD-growth of single-crystalline hexagonal bilayer graphene (BLG) flakes and mm-size BLG films with the interlayer twist...

A new mineral, johnkoivulaite, has been named in honor of John Koivula, a renowned microscopist and preeminent researcher at GIA for more than 40 years. In collaboration with scientists from the California Institute of Technology, Dr. Kyaw Thu of Macle Gem Trade Laboratory, and Nay Myo, a gem dealer from Mogok, GIA researchers described johnkoivula...

Monolayer transition-metal dichalcogenides (TMDCs) in the 2H-phase are semiconductors promising for opto-valleytronic and opto-spintronic applications because of their strong spin-valley coupling. Here we report detailed studies of opto-valleytronic properties of heterogeneous domains in CVD-grown monolayer WS₂ single crystals. By illumi...

A detailed investigation was conducted on high-pressure (~1.4 GPa) tourmaline from an Eoalpine mafic eclogite, which occurs in the Kreuzeck Mountains, Eastern Alps, Austria. Tourmaline from this locality contains the highest amount of Sr²⁺ (up to 0.68 wt% SrO) known to date. The space group is R3m with unit-cell parameters a = 15.944(1), c = 7.202(...

Davidbrownite-(NH 4), (NH 4 ,K) 5 (V 4+ O) 2 (C 2 O 4)[PO 2.75 (OH) 1.25 ] 4 ·3H 2 O, is a new mineral species from the Rowley mine, Maricopa County, Arizona, USA. It occurs in an unusual bat-guano-related, post-mining assemblage of phases that include a variety of vanadates, phosphates, oxalates and chlorides, some containing NH 4 +. Other seconda...

A quantitative understanding of nitrogen incorporation in Earth materials is important for constraining volatile evolution in planetary bodies. We used a combination of chemical (SIMS, EPMA, and laser-extraction mass spectrometry) and spectroscopic (FTIR) observations to study nitrogen contents and speciation mechanisms in silicate glasses, metal a...

Some of nature's most vivid colors occur in minerals, and tourmalines are among the most colorful species in the mineral kingdom. This array of often vivid colors is a result of the tourmalines' capacity to incorporate a wide variety of metal ions, such as iron, manganese, titanium, chromium, and vanadium into their crystal structures. Some of thes...

The incorporation of electrically tunable materials into photonic structures such as waveguides and metasurfaces enables dynamic, electrical control of light propagation at the nanoscale. Few-layer black phosphorus is a promising material for these applications due to its in-plane anisotropic, quantum well band structure, with a direct band gap tha...

The synthesis and characterization of a novel, low cost, amorphous wide-bandgap semiconductor via X-ray induced decomposition of strontium oxalate at high pressure is demonstrated. By means of IR spectroscopy, the final product is identified as a mixture of strontium carbonate, strontium oxalate and CO-derived materials. Band gap measurements demon...

Pararaisaite, Cu^(2+)Mg[Te^(6+)O_4(OH)_2] •6H_2O, is a new mineral from the North Star mine, Tintic district, Juab County, Utah, USA. It is an oxidation-zone mineral occuring in vugs in a matrix of massive quartz with embedded crystals of baryte and goldfieldite. Crystals are deep blue, striated prisms up to 0.4 mm in length, elongated on [010] and...

Bodieite (IMA2017-117), Bi^(3+)_2(Te^(4+)O_3)_2(SO_4), is a new mineral from a dump near the North Star mine, Tintic district, Juab County, Utah, and the Pittsburg-Liberty mine, Masonic district, Mono County, California, U.S.A. It is an oxidation-zone mineral occuring in vugs. Crystals occur in a variety of habits, including bladed, acicular, steep...

Ramazzoite (IMA2017-090), [Mg8Cu12(PO4)(CO3)4(OH)24(H2O)20][(H0.33SO4)3(H2O)36], is a new polyoxometalate (POM) mineral from the Monte Ramazzo mine, near Genova, Liguria, Italy. It occurs on magnetite-rich matrix in association with chlorartinite, chrysotile, dypingite, goethite, lepidocrocite and nesquehonite, and is a late-stage, secondary minera...

Ramazzoite (IMA2017-090), [Mg_8Cu_(12)(PO_4)(CO_3)_4(OH)_(24)(H_2O)_(20)][(H_(0.33)SO_4)_3(H_2O)_(36)], is a new polyoxometalate (POM) mineral from the Monte Ramazzo mine, near Genova, Liguria, Italy. It occurs on magnetite-rich matrix in association with chlorartinite, chrysotile, dypingite, goethite, lepidocrocite and nesquehonite, and is a late-...

Understanding the mechanisms of highly-active, earth-abundant water oxidn. electrocatalysts can guide the development of advanced water-splitting devices that convert renewable electricity to clean fuels. Unfortunately, catalytic intermediates are difficult to isolate and characterize because they tend to be extremely transient and present at low c...

Single crystals of strontium iodide (SrI2), an important material for nuclear detector applications, are grown commercially in cylindrical ampoules using the Bridgman self-seeding method. As a result, the axial orientation of Bridgman boules varies from run to run. Most crystal growth methods benefit from the use of oriented seeds, which can be hel...

Andradite, ideal end-member formula Ca_3Fe^(3+)_2Si_3O_(12), is one of the common rock-forming garnets found in the Earth's crust. There are several outstanding questions regarding andradite's thermodynamic and physical property behavior. Three issues are: i) Could there be differences in the thermodynamic properties, namely heat capacity, C_p, bet...

We report volatile concentrations and hydrogen isotope compositions of impact melts and minerals in EETA 79001. We observed chemical changes in pyroxene, maskelynite (or feldspathic glass), and merrillite in contact with or inside impact melts. All pyroxene grains analyzed here are inside or close to impact melt pockets and contain 10–41 ppm H2O an...

Mg‐phyllosilicate‐bearing, dark surface materials on the dwarf planet Ceres have NH4‐bearing materials, indicated by a distinctive 3.06 μm absorption feature. To constrain the identity of the Ceres NH4‐carrier phase(s), we ammoniated ground particulates of candidate materials to compare their spectral properties to infrared data acquired by Dawn's...

Encapsulating Earth's deep water filter Small inclusions in diamonds brought up from the mantle provide valuable clues to the mineralogy and chemistry of parts of Earth that we cannot otherwise sample. Tschauner et al. found inclusions of the high-pressure form of water called ice-VII in diamonds sourced from between 410 and 660 km depth, the part...

There has been much research undertaken on structural OH^– in various nominally anhydrous minerals including the common silicate garnets (i.e., X_3Y_2Si_3O_(12), where X = Mg, Fe^(2+), Mn^(2+), and Ca and Y = Al, Fe^(3+), and Cr^(3+)). However, it is still largely not understood where small concentrations of H atoms are incorporated in the garnet c...

We report in situ spectroscopic measurements in nonaqueous media designed to trap an exceptionally strong oxidant generated electrochemically from an iron-containing nickel layered double hydroxide ([NiFe]-LDH) material. Anodic polarization of this material in acetonitrile produces metal-oxo vibrational spectroscopic signatures along with an extrem...

In this paper, we discuss the occurrence of liebermannite (IMA 2013-128), KAlSi3O8, a new, shock-generated, high-pressure tetragonal hollandite-type structure silicate mineral, in the Zagami basaltic shergottite meteorite. Liebermannite crystallizes in space group I4/m with Z = 2, cell dimensions of a = 9.15 ± 0.14 (1σ) Å, c = 2.74 ± 0.13 Å, and a...

The incorporation of electrically tunable materials into photonic structures such as waveguides and metasurfaces enables dynamic control of light propagation by an applied potential. While many materials have been shown to exhibit electrically tunable permittivity and dispersion, including transparent conducting oxides (TCOs) and III-V semiconducto...

Knowing the amount and timing of water incorporation into the Moon has fundamental implications for our understanding of how the Earth–Moon system formed. Water has been detected in lunar samples but its abundance, distribution and origin are debated. To address these issues, we report water concentrations and hydrogen isotope ratios obtained by se...

The physical properties of silicate melts within Earth's mantle affect the chemical and thermal evolution of its interior. Chemistry and coordination environments affect such properties. We have measured the hyperfine parameters of iron-bearing rhyolitic and basaltic glasses up to ~120 GPa and ~100 GPa, respectively, in a neon pressure medium using...

A recent Gem Note by Williams et al. (2017) documented green/brown dravite from the Commander mine, Simanjiro District, north-eastern Tanzania. A crystal fragment that was studied for that report was subsequently analysed further by the present author to investigate the nature of its green coloration.

Kyawthuite, Bi 3+ Sb 5+ O 4 , is a new gem mineral found as a waterworn crystal in alluvium at Chaung-gyi-ah-le-ywa in the Chaung-gyi valley, near Mogok, Burma (Myanmar). Its description is based upon a single sample, which was faceted into a 1.61-carat gem. The composition suggests that the mineral formed in a pegmatite. Kyawthuite is monoclinic,...

Żabińskiite, ideally Ca(Al0.5Ta0.5)(SiO4)O, was found in a Variscan granitic pegmatite at Piława Górna, Lower Silesia, SW Poland. The mineral occurs along with (Al,Ta,Nb)- and (Al,F)-bearing titanites, a pyrochlore-supergroup mineral and a K-mica in compositionally inhomogeneous aggregates, ∼120 μm × 70 μm in size, in a fractured crystal of zircon...

Ammonciated- and phyllosilicatebearing materials were discovered on Ceres and globally mapped with the VIR imaging spectrometer on the Dawn mission [1-3]. Key Ceres infrared spectral features are located at ~3.05 µm, indicating NH4-bearing materials, and 2.72 µm, indicating Mg-OH-bearing materials. Their co-occurrence everywhere on the surface [3]...

In its pure and perfect form, diamond is colorless. However, in nature or even when made in a laboratory, diamonds are never composed just of perfectly arranged carbon atoms. At the atomic level even colorless and seemingly flawless diamonds contain trace amounts of other elements such as nitrogen or hydrogen, or they may contain structural defects...

Wayneburnhamite (IMA2015-124), Pb9Ca6(Si2O7)3(SiO4)3, is a new mineral from the Commercial quarry, Crestmore, Riverside County, California, where it occurs as a metasomatic mineral on fracture surfaces in vesuvianite/wollastonite rock. Wayneburnhamite crystals are sky-blue hexagonal tablets and prisms up to 0.5 mm in maximum dimension. The streak i...

Vesuvianite from Pajsberg, Sweden contains about one atom of Mn, based on 50 cations per formula unit, and small amounts of Be, B, and As. Optical absorption analysis suggests that the Mn is predominantly or entirely trivalent. Crystal-structure analysis indicates that Mn is housed at the general octahedral site Y3, which exhibits only minor distor...

Andychristyite, PbCu 2+ Te 6+ O 5 (H 2 O), is a new tellurate mineral from Otto Mountain near Baker, California, USA. It occurs in vugs in quartz in association with timroseite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Andychristyite is triclini...

Magnesian calcites are important components of sediments and biominerals. Although Raman spectra of calcite, dolomite, and magnesite are well known, those of magnesian calcites deserve further investigation. Nineteen syntheses of magnesian calcites covering the range 0–50 mol% MgCO 3 have been carried out at high pressure and temperature (1–1.5 GPa...

Ahrensite (IMA 2013-028), γ-Fe_2SiO_4, is the natural Fe-analog of the silicate-spinel ringwoodite (γ-Mg_2SiO_4). It occurs in the Tissint Martian meteorite, where it forms through the transformation of the fayalite-rich rims of olivine megacrysts or Fe-rich microphenocrysts in contact with shock melt pockets. The typical sequence of phase assembla...

Fluor-schorl, NaFe^(2+) _3Al_6Si_6O_(18)(BO_3)_3(OH)_3F, is a new mineral species of the tourmaline supergroup from alluvial tin deposits near Steinberg, Zschorlau, Erzgebirge (Saxonian Ore Mountains), Saxony, Germany, and from pegmatites near Grasstein (area from Mittewald to Sachsenklemme), Trentino, South Tyrol, Italy. Fluor-schorl was formed as...

We present recent developments in time-resolved Raman spectroscopy instrumentation and measurement techniques for in situ planetary surface exploration, leading to improved performance and identification of minerals and organics. The time-resolved Raman spectrometer uses a 532 nm pulsed microchip laser source synchronized with a single photon avala...

The mantle is the major reservoir of Earth's water, hosted within Nominally Anhydrous Minerals (NAMs) (e.g., Bell and Rossman, 1992; Peslier et al., 2010; Peslier, 2010; Nestola and Smyth, 2015), in the form of hydrogen bonded to the silicate's structural oxygen. From whence cometh this water? Is the water in these minerals representative of the Ea...

Gem-quality cordierite is typically seen as blue material (iolite), showing strong pleochroism in yellow, light blue and dark violet-blue. However, in late 2014 one of the authors (FP) learned about a new occurrence of a much different cordierite, which typically ranged from dark orange-red to yellowish brown. The material is recovered by local min...

During the 2016 Tucson gem shows, Todd Wacks (Tucson Todd’s Gems, Tucson, Arizona, USA) showed author BML a yellow 11.13 ct tourmaline that he faceted from a piece of rough recently obtained on a buying trip to Tanzania by Sir-Faraz Ahmad (Farooq) Hashmi (Intimate Gems, Glen Cove, New York, USA). The rough material was reportedly found in October–N...

Silicon stable isotopes are fractionated by a host of low-temperature aqueous processes, making them potentially useful as a weathering proxy. Here we characterize the silicon isotope signature of surficial chemical weathering of glassy basaltic lava flows at Kilauea Volcano, Hawaii. Fresh basalt flow surfaces (〈40 years old) frequently feature opa...

We report unambiguous chemical evidence for subsurface water activity in the martian crust at <600 Ma based on the data from Tissint, a fresh martian meteorite fall with minimal terrestrial weathering. The impact-melt pockets in Tissint contain abundant volatiles (H2O, CO2, F, and Cl), and their concentrations are positively correlated with each ot...

IMA No. 2015-033 Żabińskiite Ca[Al0.5(Ta,Nb)0.5)](SiO4)O Piława Górna migmatite-amphibolite quarry, Sudetes, ~50 km south-west of Wrocław, Poland (50º42’11.77’’N, 16º44’12.36’’E) Adam Pieczka*, Frank C. Hawthorne, Chi Ma, George R. Rossman, Philippe Buffat, Bogdan Rutkowski, Eligiusz Szełęg, Adam Szuszkiewicz, Krzysztof Turniak, Krzysztof Nejbert a...

Tissintite is a new vacancy-rich, high-pressure clinopyroxene, with a composition essentially equivalent to plagioclase. It was discovered in maskelynite (shocked plagioclase) and is commonly observed included within, or in contact with, shock-melt pockets in the Tissint meteorite, a depleted olivine-phyric shergottite fall from Mars. The simple co...

Recent interest in hydrogen incorporation in feldspars has been driven by the potential of this common mineral species to record magmatic water contents. Accurate measurement of H concentrations in feldspars by Fourier transform infrared (FTIR) spectroscopy is hampered by the need to collect polarized spectra in three mutually perpendicular directi...

A scanning probe image of single-layer MoS2 trapping water on a mica surface is depicted on the left, with its corresponding photoluminescence image depicted on the right. The trapped water strongly quenches the fluorescence of single-layer MoS2 and distinctly affects its optical properties. The work by J. R. Heath and co-workers on page 2734 highl...

During the June 2015 JCK gem and jewellery show in Las Vegas, Nevada, USA, news circulated about some attractive new purple garnets from East Africa. Gem dealer Geoffrey Watt (Mayer & Watt, Maysville, Kentucky, USA) had an intense purple 3.87 ct cushion (Figure 5, centre), which was one of two faceted purple garnets that he bought from a Sri Lankan...

Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth's mantle. One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this impor...

Optical spectroscopy is concerned with the measurement of the absorption, reflection and emission of light in the near-ultraviolet (~250 nm) through the mid-infrared (~3000 nm) portions of the spectrum. The human interface to the geological and mineralogical world is primarily visual. Optical spectroscopy is, in particular, well suited to investiga...

Bluebellite, Cu_6[I^(5+)O_3(OH)_3](OH)_7Cl and mojaveite, Cu_6[Te^(6+)O_4(OH)_2](OH)_7Cl, are new secondary copper minerals from the Mojave Desert. The type locality for bluebellite is the D shaft, Blue Bell claims, near Baker, San Bernardino County, California, while cotype localities for mojaveite are the E pit at Blue Bell claims and also the Bi...

An optical instrument we refer to as the “biaxial orientation device” has been developed for finding the optical plane, acute bisectrix, and obtuse bisectrix in biaxial crystals by means of optically aligning conoscopically formed melatopes and measuring the angular coordinates of the melatopes, where the angular values allow for determination of t...