Ominelite, (Fe,Mg)Al3BSiO9(Fe2+analogue of grandidierite), a new mineral from porphyritic granite in Japan

Hiroi, Yoshikuni; Motoyoshi, Yoichi; Peacor, Donald R.; Rouse, Roland C.; Matsubara, Satοshi; Yokoyama, Kenichi; Miyawaki, Ritsuro; McGee, J. J.; Su, Shu-Chun; Hokada, Tomokazu; Furukawa, Noboru; Shibasaki, Hiroshi

doi:10.2138/am-2002-0117

Cited by 19 publications

(7 citation statements)

References 24 publications

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“…Cr, Sr, P, and Ni are below the detection limit (<0.02 wt.%). Speer, 1981Armbruster, 1985;Orlandi and Pezzotta, 1993;Spiridonov et al, 1994;Černý et al, 1997;Geiger et al, 2000;Khomenko et al, 2001;Malcherek et al, 2001;Hiroi et al, 2002;Gottesmann and Förster, 2004;Anan'ev and Reverdatto, 1997;Kalt et al, 1999;Fediuk, 2001;Fediuk and Fediuková, 2003;Žáček, 2004). Fine = a fine-grained zone near the contact with clinker; coarse = a coarse-grained zone; vug = associations around and in vugs; inc. = inclusions in large, low-calcium pyroxene crystals from vugs; c, r, out designate the core, rim, and outermost part of a grain.…”

Section: Mineral Chemistry Of the Ravat Paralavamentioning

confidence: 99%

Mineralogy and Origin of Fayalite–Sekaninaite Paralava: Ravat Coal Fire, Central Tajikistan

Sharygin¹,

Sokol²,

Belakovsky³

2015

Coal and Peat Fires: A Global Perspective

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Section: Mineral Chemistry Of the Ravat Paralavamentioning

confidence: 99%

Mineralogy and Origin of Fayalite–Sekaninaite Paralava: Ravat Coal Fire, Central Tajikistan

Sharygin¹,

Sokol²,

Belakovsky³

2015

Coal and Peat Fires: A Global Perspective

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“…However, from room-temperature to about 1098 K (a a ¼ a c ), anisotropy of thermal expansion is most pronounced along the a-axis whereas at temperatures higher than 1098 K, expansion is dominated along the c-axis. Grandidierite (Mg, Fe 2+ )Al 3 BSiO 9 , is the Mg-rich member of the grandidieriteominelite series (Dzikowski et al 2007;Hiroi et al 2001) and is of particular interest because it contains both Al and (Mg, Fe) in fivefold coordination (MacKenzie and Meinhold 1997;Dzikowski et al 2007;Farges 2001). Structure refinement of single-crystal XRD room-temperature data indicated an almost pure Mg endmember with 97.3(3)% Mg and 2.7(3)% Fe for the selected sample.…”

Section: Thermal Evolution Of Al 4 B 2 Omentioning

confidence: 99%

Thermal Expansion of Aluminoborates

Fisch

Armbruster

2011

Minerals as Advanced Materials II

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“…The refractive indices of grandidierite and ominelite (Fe 2+ , Mg)Al 3 BSiO 9 -the recently described Fe analogue of grandidierite (Hiroi et al, 2002)-are closely related to the iron content; with increasing Fe, the R.I. also increases (table 3). With increasing iron values, specific gravity in grandidierite also increases, from 2.91 to 2.99 (Olesch and Seifert, 1976).…”

Section: Discussionmentioning

confidence: 94%

“…Refractive indices and iron content of grandidierite and ominelite from various localities. All data are for grandidierite, (Mg, Fe 2+ )Al 3 BSiO 9 , exceptHiroi et al (2002) for ominelite, (Fe 2+ , Mg)Al 3 BSiO 9 , the Fe analogue of grandidierite. Abbreviation: nr = not reported.…”

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confidence: 99%

The First Transparent Faceted Grandidierite, From Sri Lanka

Schmetzer¹,

Burford²,

Kiefert³

et al. 2003

Gems & Gemology

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randidierite, a magnesium-aluminum borosilicate, MgAl 3 BSiO 9 , is mentioned only rarely as a "possible" blue gemstone (Ostwald, 1964), although the existence of faceted stones has been reported occasionally in the gemological literature (see, e.g., Mitchell, 1977). However, the samples available to date as faceted stones or cabochons, all originating from southern Madagascar, are opaque-never transparent-or at best translucent (Arem, 1987). This article describes the first transparent faceted grandidierite, which is also the first faceted grandidierite reported from Sri Lanka.Grandidierite occurs in pegmatites, contact metamorphic rocks (hornfelses), and high-grade (granulite facies) metamorphic rocks; worldwide about 40 localities are known (Grew, 1996). Grandidierite was first discovered in a pegmatitic environment at Andrahomana near Taolanaro (formerly Fort Dauphin) in southeastern Madagascar (Lacroix, 1902(Lacroix, , 1904. The orthorhombic mineral was named by Lacroix after Alfred Grandidier, one of the French explorers of Madagascar. Lacroix described the nontransparent material as both massive (1902) and forming crystals as long as 8 cm (1904). The color of grandidierite from different localities is described as blue, greenish blue, blue-green, and bluish green.The Kolonne area of Sri Lanka, which is located approximately 8 km south-southeast of Rakwana, near Ratnapura, has become known for some rare gem materials such as sapphirine (Harding and Zoysa, 1990), olivine with a high iron content (Burford and Gunasekera, 2000), and-most recently-the Ca-Mg-Al borosilicate serendibite (Schmetzer et al., 2002). In 2000 while in Ratnapura, one of the authors (MB) purchased the grandidierite described in this article, reportedly from the Kolonne area, as an 0.85 ct crystal fragment. After faceting, the rough yielded a 0.29 ct greenish blue transparent gemstone (figure 1).The Sri Lankan seller offered the rough gem (on the basis of its color) as a "possible serendibite." The original flat, tabular crystal did not appear to be water worn. Probably it was mined from a primary deposit, as is the case for most sapphirine from high-grade metamorphic host rocks in the Kolonne area (see again Harding and Zoysa, 1990). Based on some initial testing, the owner believed that the stone might be the rare gem mineral grandidierite and sent it to the senior author (KS) for additional tests and confirmation. MATERIALS AND METHODSThe faceted grandidierite was tested by standard gemological methods for refractive indices, optic character, specific gravity, and fluorescence to longand short-wave ultraviolet radiation, as well as the

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Ominelite, (Fe,Mg)Al₃BSiO₉(Fe²⁺analogue of grandidierite), a new mineral from porphyritic granite in Japan

Cited by 19 publications

References 24 publications

Mineralogy and Origin of Fayalite–Sekaninaite Paralava: Ravat Coal Fire, Central Tajikistan

Mineralogy and Origin of Fayalite–Sekaninaite Paralava: Ravat Coal Fire, Central Tajikistan

Thermal Expansion of Aluminoborates

The First Transparent Faceted Grandidierite, From Sri Lanka

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