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![First thumbnail for: EVIDENCE OF EVAPORITES IN THE GENESIS OF THE VANAD...]()
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![The use of trace-element chemistry of tsavorites from the Neoproterozoic Metamorphic Mozambique Belt for geographical origin determination. (a) The diagram vanadium vs. chromium contents (in ppm) illustrates the usefulness of the V/Cr ratio for separating Kenyan tsavorites from the other worldwide deposits. (b) Attempt to refine the geographic origin of tsavorites considering the upper and lower limits of V and Cr contents for the determination of geographic boxes. Kenyan tsavorites have distinct Cr-contents and constant V/Cr ratio for each deposit which permits to pinpoint the origin of different mines. Pakistani and Madagascar tsavorite fields are overlapping but the high contents of vanadium and chromium for some Pakistani tsavorites can be used for deciphering the origin. Antarctic tsavorites have a specific chemical signature with a high V/Cr ratio.]()
![Sm-Nd isochrons calculated for different sets of samples to determine the age of the tsavorite and tanzanite mineralization from Kenya, Tanzania, and Madagascar. (A) All samples (n = 19) from the NMMB, except the tsavorite from Baraka, Kenya. (B) All tsavorites (n = 4) and tanzanites (n = 5) from the deposits located in the Lelatema fold belt in northern Tanzania, except the tanzanite from Karot. (C) All tsavorites (n = 4) from the deposits located in the Lelatema fold belt. (D) All tanzanites (n = 5) from the deposits located in the Lelatema Fold Belt, except the tanzanite from Karot.]()
![First thumbnail for: Fluorescence of trivalent neodymium in various mat...]()
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![(a, b, c) Mineralisation in vugs in Block D′ mine in Merelani; the dark colour of the rock and the dirt on the hands is due to the presence of disseminated graphite in the gneiss. (a, c) Tanzanite (Tz), quartz and pyrite found in pressure shadows between boudins. (b) Pyrite, quartz, and green gem mineral (Tr – tremolite?) in the same area of the mine as (a) and (b). Note that the green mineral could be either diopside or tremolite. They have identical colour and can only be distinguished when broken to reveal the cleavage. These minerals are often described as tsavorite by mine personel. (d) Tsavorite nodule in calc-silicate rocks from the ‘Tsavorite Mine’. This sample was given to us at the mine, but its specific location is unknown. (e) Garnet kyanite schist in the Block D′ mine. (f) Garnet kyanite schist at the tsavorite mine.]()
![(A) Tectonic map of Kenya and Tanzania (modified after Fritz et al. 2013) with the location of the tsavorite and tanzanite deposits studied in this paper. (B) Tectonic map of Madagascar (modified after Fritz et al. 2013) with the location of the tsavorite deposits studied in this paper. (C) Geological sketch map of SE Kenya and NE Tanzania (modified after Tenczer et al. 2013) showing the tsavorite and tanzanite deposits studied in this paper. ANS: Arabian Nubian Shield; EG: Eastern Granulite; WG: Western Granulite.]()
![Ternary diagram goldmanite–grossular–uvarovite for tsavorites from different deposits of the Neoproterozoic Metamorphic Mozambique Belt. Distribution of the chemical data of tsavorite by countries and deposits.]()
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![UV-Vis-NIR absorption spectra of the different types of tsavorite. The absorption value is indicated for the lowest spectrum, while the others are vertically shifted for better visibility. ‘A’ is for instrumental artifact. The different types of tsavorite: (2a) type 1 (with V > Cr > Mn); (2b) type 2 (with V >Mn >Cr); (2c) type 3 (with Mn >V >Cr); (2d) type 4 (with Mn >Cr >V), and (2e) type 5 (with Cr >Mn >V). The high contents of V and Cr of the Pakistani tsavorite (samples JAM-1e and JAM-1a) and the high thickness of the crystal plate explain the poor quality of the absorption spectra (Fig. 2a) in the high-energy region. TAN = Tanzania, PAK = Pakistan, MAD = Madagascar, ANT = Antarctica, KEN = Kenya.]()
![First thumbnail for: ORIGIN OF TANZANITE AND ASSOCIATED GEMSTONE MINERA...]()
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![Simplified geological map showing tsavorite occurrences in eastern Africa. (1) Metamagmatic rocks undivided, (2) granulitic rocks undivided, (3) undivided metasediments hosting marbles, (4) Karoo sediments and Neogene volcanics, (5) tsavorite occurrences in green, and Rockland ruby mine in red, (6) Normal fault, (7) Thrust zone (modified from Fritz et al. 2009, Le Goff et al. 2010, Feneyrol et al. 2013).]()
![Back-scattered electron images of: (a) Anhydrite (Anh) inclusion associated with F-rich tremolite (F-Tr) and dolomite (Dol) in lens I. (b) Anhydrite (Anh) within the carbonated nodule. (c) Multiphase fluid inclusion cavity within diopside (Di) from lens II containing anhydrite (Anh), native sulfur (S), molybdenite (Mo), and calcite (Cal). (d) Fluid inclusion cavity within tsavorite (Ts) filled by tsavorite and anhydrite (Anh).]()
![Tsavorite (3.5 × 3.8 cm; left), Collection Crystal Classics. Tanzanite (8.7 × 5 × 3cm; right), Collection Marcus Budil, Merelani, Tanzania. Photographs: L.-D. Bayle, le Règne Minéral.]()
![Fluid inclusion (FI) assemblages in tanzanite pockets and tsavorite-bearing quartz veins from Merelani in Tanzania (transmitted light). (A–D) Tanzanite. (E–F) Tsavorite. (A) Primary multiphase H2S-dominated FI (liquid [lH2S] + vapor [vH2S]) with native sulfur (S8), phengite (phg), and calcite (Ca). (B) Flat and elongated primary multiphase H2S-dominated FI (lH2S + vH2S) with native sulfur (S8), phengite (phg), and graphite (gr). (C) Relationship between primary (Type I) and secondary (Type II) FI. The field of primary FI is overlapped by a dark secondary FI which is also H2S-dominated (lH2S + vH2S) with native sulfur and graphite (same symbols as B). (D) The secondary FI with phengite, graphite, and native sulfur. (E) Primary multiphase FI with liquid- and vapor-H2S containing a crystal of native sulfur (S8). (F) Multiphase dismembered FI hosting native sulfur (S8) and VH2S + LH2S displaying neonate FI.]()
![Secondary fluid inclusions found in one tsavorite wafer from Merelani mines, Tanzania. (A) Mixing of two different types of fluid inclusions (FI). Monophase FI (lc) in the CO2–H2S–COS–S8±(CH4)±(N2) system (Type IIA) associated with biphase aqueous FI (V + LH2O, Type IIC). In these fields, one monophase CH4-N2±(CO2)-bearing FI (Type IIB) was identified by microthermometry and Raman spectroscopy. Ttn = titanite. (B) Monophase CO2-H2S-COS-S8±(CH4)±(N2) FI (lc, Type IIA) with an oblong cavity. (C) Cavity of dark monophase Type IIA FI formed around a euhedral crystal of garnet (Grt) which has the same Raman spectrum as the host-tsavorite. (D) Type IIA FI showing the presence of a rim of liquid H2O around the carbonic CO2-H2S-dominated carbonic phase (lc + Vc).]()
![Crystal of tsavorite associated with graphite and calcite from Merelani (Tanzania). Crystal length = 2 cm. Photograph: L.-D. Bayle/le Règne Minéral.]()
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Journal Article
Chronological Constraints On Tsavorite Mineralizations and Related Metamorphic Episodes In Southeast Kenya Available to Purchase
Journal: The Canadian Mineralogist
Publisher: Mineralogical Association of Canada
Published: 01 September 2017
The Canadian Mineralogist (2017) 55 (5): 845–865.
...Jean-Emmanuel Martelat; Jean-Louis Paquette; Valerie Bosse; Gaston Giuliani; Patrick Monié; Edward Omito; Cédric Simonet; Daniel Ohnenstetter; Daniel Ichang'i; Christopher Nyamai; Abigail Wamunyu Abstract Tsavorite is exclusively hosted in the Neoproterozoic Metamorphic Mozambique Belt (NMMB...
FIGURES
Journal Article
Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt Available to Purchase
Journal: The Canadian Mineralogist
Publisher: Mineralogical Association of Canada
Published: 01 July 2017
The Canadian Mineralogist (2017) 55 (4): 763–786.
...Julien Feneyrol; Gaston Giuliani; Daniel Demaiffe; Daniel Ohnenstetter; Anthony E. Fallick; Jean Dubessy; Jean-Emmanuel Martelat; Amos Fety Michel Rakotondrazafy; Edward Omito; Daniel Ichang'i; Christopher Nyamai; Abigail Wambui Wamunyu Abstract The genetic model previously proposed for tsavorite...
FIGURES
Journal Article
New typology and origin of tsavorite based on trace-element chemistry Available to Purchase
Journal: European Journal of Mineralogy
Publisher: GeoScienceWorld Journals
Published: 01 March 2014
European Journal of Mineralogy (2014) 26 (2): 293–308.
...Julien Feneyrol; Gaston Giuliani; Daniel Ohnenstetter; Benjamin Rondeau; Emmanuel Fritsch; Anthony E. Fallick; Daniel Ichang’i; Edward Omito; Michel Rakotondrazafy; Madison Ranatsenho; Florent Lallier Abstract New electron-microprobe analyses of ‘tsavorites’ from the Neoproterozoic Metamorphic...
FIGURES
Book Chapter
TSAVORITE AND TANZANITE DEPOSITS Available to Purchase
Series: Short Courses
Publisher: Mineralogical Association of Canada
Published: 01 January 2014
DOI: 10.3749/9780921294696.ch07
EISBN: 978-0-921294-69-6
... INTRODUCTION These two beautiful gemstones, one blue-violet, “tanzanite” ( Plate 7-1a, b, c ), and one green, “tsavorite” ( Plate 7-1e, f, g ), are very closely related in terms of their chemistry and mode of occurrence ( Walton & Marshall 2007 ). They are two of the more successful...
Journal Article
EVIDENCE OF EVAPORITES IN THE GENESIS OF THE VANADIAN GROSSULAR ‘TSAVORITE’ DEPOSIT IN NAMALULU, TANZANIA Available to Purchase
Journal: The Canadian Mineralogist
Publisher: Mineralogical Association of Canada
Published: 01 June 2012
The Canadian Mineralogist (2012) 50 (3): 745–769.
...Julien Feneyrol; Daniel Ohnenstetter; Gaston Giuliani; Anthony E. Fallick; Claire Rollion-Bard; Jean-Louis Robert; Elias P. Malisa Abstract The Namalulu tsavorite (vanadian grossular up to 0.80 wt.% V 2 O 3 ) deposit in northeastern Tanzania occurs in metasomatized graphitic gneiss overlain...
FIGURES
Image
The use of trace-element chemistry of tsavorites from the Neoproterozoic Me... Available to Purchase
in New typology and origin of tsavorite based on trace-element chemistry
> European Journal of Mineralogy
Published: 01 March 2014
Fig. 6 The use of trace-element chemistry of tsavorites from the Neoproterozoic Metamorphic Mozambique Belt for geographical origin determination. (a) The diagram vanadium vs . chromium contents (in ppm) illustrates the usefulness of the V/Cr ratio for separating Kenyan tsavorites from the other
Image
Sm-Nd isochrons calculated for different sets of samples to determine the a... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
Fig. 3. Sm-Nd isochrons calculated for different sets of samples to determine the age of the tsavorite and tanzanite mineralization from Kenya, Tanzania, and Madagascar. (A) All samples ( n = 19) from the NMMB, except the tsavorite from Baraka, Kenya. (B) All tsavorites ( n = 4) and tanzanites
Journal Article
Fluorescence of trivalent neodymium in various materials excited by a 785 nm laser Available to Purchase
Journal: American Mineralogist
Publisher: Mineralogical Society of America
Published: 01 February 2014
American Mineralogist (2014) 99 (2-3): 332–342.
... ionic-radius match to substitute for Ca 2+ and an arrangement of energy levels to produce fluorescence in the frequency-shift range of interest. Raman/fluorescence spectra of six calcium-based minerals, namely fluorite, calcite, powellite, scheelite, apatite, and grossular/tsavorite, have been obtained...
FIGURES
Image
( a , b , c ) Mineralisation in vugs in Block D′ mine in Merelani; the da... Available to Purchase
in ORIGIN OF TANZANITE AND ASSOCIATED GEMSTONE MINERALIZATION AT MERELANI, TANZANIA
> South African Journal of Geology
Published: 01 June 2014
, quartz, and green gem mineral (Tr – tremolite?) in the same area of the mine as ( a ) and ( b ). Note that the green mineral could be either diopside or tremolite. They have identical colour and can only be distinguished when broken to reveal the cleavage. These minerals are often described as tsavorite
Image
(A) Tectonic map of Kenya and Tanzania (modified after Fritz et al . 2013... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
Fig. 2. (A) Tectonic map of Kenya and Tanzania (modified after Fritz et al . 2013 ) with the location of the tsavorite and tanzanite deposits studied in this paper. (B) Tectonic map of Madagascar (modified after Fritz et al . 2013 ) with the location of the tsavorite deposits studied
Image
Ternary diagram goldmanite–grossular–uvarovite for tsavorites from differen... Available to Purchase
in New typology and origin of tsavorite based on trace-element chemistry
> European Journal of Mineralogy
Published: 01 March 2014
Fig. 4 Ternary diagram goldmanite–grossular–uvarovite for tsavorites from different deposits of the Neoproterozoic Metamorphic Mozambique Belt. Distribution of the chemical data of tsavorite by countries and deposits.
Image
δ 34 S ISOTOPIC COMPOSITION OF SULFIDES (PYRITE AND SPHALERITE) ASSOCIATED ... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
TABLE 4. δ 34 S ISOTOPIC COMPOSITION OF SULFIDES (PYRITE AND SPHALERITE) ASSOCIATED WITH TSAVORITE AND TANZANITE FROM THE LELATEMA FOLD BELT DEPOSITS IN NORTHERN TANZANIA (LEMSHUKU, MERELANI, NAMALULU DEPOSITS) AND FROM THE RUANGWA TSAVORITE DEPOSIT IN SOUTHERN TANZANIA
Image
UV-Vis-NIR absorption spectra of the different types of tsavorite. The abso... Available to Purchase
in New typology and origin of tsavorite based on trace-element chemistry
> European Journal of Mineralogy
Published: 01 March 2014
Fig. 2 UV-Vis-NIR absorption spectra of the different types of tsavorite. The absorption value is indicated for the lowest spectrum, while the others are vertically shifted for better visibility. ‘A’ is for instrumental artifact. The different types of tsavorite: (2a) type 1 (with V > Cr
Journal Article
ORIGIN OF TANZANITE AND ASSOCIATED GEMSTONE MINERALIZATION AT MERELANI, TANZANIA Available to Purchase
Journal: South African Journal of Geology
Publisher: Geological Society of South Africa
Published: 01 June 2014
South African Journal of Geology (2014) 117 (1): 15–30.
..., quartz, and green gem mineral (Tr – tremolite?) in the same area of the mine as ( a ) and ( b ). Note that the green mineral could be either diopside or tremolite. They have identical colour and can only be distinguished when broken to reveal the cleavage. These minerals are often described as tsavorite...
FIGURES
Image
Simplified geological map showing tsavorite occurrences in eastern Africa. ... Available to Purchase
in Chronological Constraints On Tsavorite Mineralizations and Related Metamorphic Episodes In Southeast Kenya
> The Canadian Mineralogist
Published: 01 September 2017
Figure 1. Simplified geological map showing tsavorite occurrences in eastern Africa. (1) Metamagmatic rocks undivided, (2) granulitic rocks undivided, (3) undivided metasediments hosting marbles, (4) Karoo sediments and Neogene volcanics, (5) tsavorite occurrences in green, and Rockland ruby mine
Image
Back-scattered electron images of: (a) Anhydrite (Anh) inclusion associated... Available to Purchase
in EVIDENCE OF EVAPORITES IN THE GENESIS OF THE VANADIAN GROSSULAR ‘TSAVORITE’ DEPOSIT IN NAMALULU, TANZANIA
> The Canadian Mineralogist
Published: 01 June 2012
), native sulfur (S), molybdenite (Mo), and calcite (Cal). (d) Fluid inclusion cavity within tsavorite (Ts) filled by tsavorite and anhydrite (Anh).
Image
Tsavorite (3.5 × 3.8 cm; left), Collection Crystal Classics. Tanzanite (8.7... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
Fig. 1. Tsavorite (3.5 × 3.8 cm; left), Collection Crystal Classics. Tanzanite (8.7 × 5 × 3cm; right), Collection Marcus Budil, Merelani, Tanzania. Photographs: L.-D. Bayle, le Règne Minéral.
Image
![Fluid inclusion (FI) assemblages in tanzanite pockets and tsavorite-bearing quartz veins from Merelani in Tanzania (transmitted light). (A–D) Tanzanite. (E–F) Tsavorite. (A) Primary multiphase H2S-dominated FI (liquid [lH2S] + vapor [vH2S]) with native sulfur (S8), phengite (phg), and calcite (Ca). (B) Flat and elongated primary multiphase H2S-dominated FI (lH2S + vH2S) with native sulfur (S8), phengite (phg), and graphite (gr). (C) Relationship between primary (Type I) and secondary (Type II) FI. The field of primary FI is overlapped by a dark secondary FI which is also H2S-dominated (lH2S + vH2S) with native sulfur and graphite (same symbols as B). (D) The secondary FI with phengite, graphite, and native sulfur. (E) Primary multiphase FI with liquid- and vapor-H2S containing a crystal of native sulfur (S8). (F) Multiphase dismembered FI hosting native sulfur (S8) and VH2S + LH2S displaying neonate FI.](https://gsw.silverchair-cdn.com/gsw/Content_public/Journal/canmin/55/4/10.3749_canmin.1600085/2/s_i1499-1276-55-4-763-f05.png?Expires=2147483647&Signature=XpnSJDCP1AClX01rxEB-UZ9ux0qC7VFEaaaSCBw6piCs3K65NkXGpTPMi9nSuX4fCafwZU1jeWRmz8STuxOP6sS3voQcn93~OtBUcTpPkXwaAwOtK0UMDnoFuwLH5N1EWkyXJ-6h-mwEkMkQc9BPvD14z4gkhxi4cNEPc3U~C1w5u-L9JaqF68Zqv5o6Eggjp4wk6jYzpYOrnDgPn5vQvRiDE~kG4IgFY91Pn9TMfbId0JBstIqLb4KMtV2lkYdJSR2AdYDeE2qfFzEe6~XWtEO0yNqVdl8zT0xSQFMx8U8HrF7i79lcENCAk04doduzzixQxiC-l9sWotsCX1rBvw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Fluid inclusion (FI) assemblages in tanzanite pockets and tsavorite-bearing... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
Fig. 5. Fluid inclusion (FI) assemblages in tanzanite pockets and tsavorite-bearing quartz veins from Merelani in Tanzania (transmitted light). (A–D) Tanzanite. (E–F) Tsavorite. (A) Primary multiphase H 2 S-dominated FI (liquid [l H2S ] + vapor [v H2S ]) with native sulfur (S 8 ), phengite (phg
Image
Secondary fluid inclusions found in one tsavorite wafer from Merelani mines... Available to Purchase
in Age and Origin of the Tsavorite and Tanzanite Mineralizing Fluids in the Neoproterozoic Mozambique Metamorphic Belt
> The Canadian Mineralogist
Published: 01 July 2017
Fig. 9. Secondary fluid inclusions found in one tsavorite wafer from Merelani mines, Tanzania. (A) Mixing of two different types of fluid inclusions (FI). Monophase FI (lc) in the CO 2 –H 2 S–COS–S 8 ±(CH 4 )±(N 2 ) system (Type IIA) associated with biphase aqueous FI (V + LH 2 O, Type IIC
Image
Crystal of tsavorite associated with graphite and calcite from Merelani (Ta... Available to Purchase
in New typology and origin of tsavorite based on trace-element chemistry
> European Journal of Mineralogy
Published: 01 March 2014
Fig. 1 Crystal of tsavorite associated with graphite and calcite from Merelani (Tanzania). Crystal length = 2 cm. Photograph: L.-D. Bayle/le Règne Minéral.
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