This diamond mine was opened around 1867 following the discovery of diamonds in the nearby Água Suja stream, a tributary of the Bagagem river. The mine closed in 1984. While most diamonds in the Coromandel district were obtained from alluvial deposits, at Romaria diamonds were mined from a lithified conglomerate in the river bottomland. This conglomerate has been interpreted as a debris flow deposit consisting of materials reworked from surrounding metasedimentary bedrock including the Neoproterozoic Araxá Group and Cretaceous sedimentary rocks (Suguio et al., 1979; Andrade and Chaves, 2009). As the debris flow apparently followed modern topographic contours, it is most likely of Quaternary age. Fleischer (1998), however, presented evidence that normal block faulting led to erosion of the original diamondiferous conglomerate on the upthrown (west) side of the faults, with deposition occurring in alluvial fans on the down-dropped side. He correlated localized outcrops of this material for a little over 40 km in an NW-SE direction and suggested the existence of a faulted lineament along nearly the entire length of the Bagagem River valley. The diamonds were probably reworked from the Mata da Corda Group of Late Cretaceous age, a resistant unit that caps the mesas on either side of the Bagagem River valley.

Lithic clasts in the conglomerate are up to 0.8 meters in size and include schist, phyllite, quartzite, basalt, reworked conglomerate, vein quartz, and siliceous concretions rich in opal. The matrix is arenaceous and contains considerable kaolinite and illite. Framework grains include mm-scale grains of heavy minerals including pyrope, staurolite, "hornblende," epidote, kyanite, monazite, tourmaline, zircon, and anatase. The opaques include magnetite, hematite, goethite, and ilmenite. The pyrope is chromium-rich, with chromium/calcium oxide ratios plotting mostly in the G4, G5, and G9 fields, indicating the poor likelihood of associated diamonds (Grütter et al., 2004). Nevertheless, diamonds from the area are large and clear, although commonly abraded and fractured, and suggest a proximal source, however, that has yet to be identified.

Modified by NK, January 2017.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Mineral List

18 valid minerals.

Detailed Mineral List:

ⓘ Almandine

Formula: Fe²⁺₃Al₂(SiO₄)₃

References:

Chaves, M. L. S. C., and Svisero, D. P., 1993, Características geológicas e origem conglomerados diamantíferos das regiões de Diamantina (Mesoproterozóico) e de Romaria (Cretáceo Superior), Minas Gerais: Boletim Instituto Geociências, Univ.São Paulo, Séries Cient., v. 24, p. 49-57.

ⓘ Anatase

Formula: TiO₂

References:

ⓘ Diamond

Formula: C

References:

Fleischer, R. (1998) A rift model for the sedimentary diamond deposits of Brazil. Mineralium Deposita, 33 (3) 238-254 doi:10.1007/s001260050144

ⓘ Epidote

Formula: (CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)

References:

ⓘ Goethite

Formula: Fe³⁺O(OH)

References:

ⓘ Grossular

Formula: Ca₃Al₂(SiO₄)₃

References:

ⓘ Hematite

Formula: Fe₂O₃

References:

ⓘ Ilmenite

Formula: Fe²⁺TiO₃

ⓘ Kaolinite

Formula: Al₂(Si₂O₅)(OH)₄

References:

ⓘ Kyanite

Formula: Al₂(SiO₄)O

References:

ⓘ Magnetite

Formula: Fe²⁺Fe³⁺₂O₄

ⓘ 'Monazite Group'

Formula: REE(PO₄)

References:

ⓘ Muscovite

Formula: KAl₂(AlSi₃O₁₀)(OH)₂

References:

ⓘ Muscovite var. Illite

Formula: K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂

References:

ⓘ Opal

Formula: SiO₂ · nH₂O

References:

ⓘ Perovskite

Formula: CaTiO₃

ⓘ Pyrope

Formula: Mg₃Al₂(SiO₄)₃

ⓘ Quartz

Formula: SiO₂

References:

ⓘ Rutile

Formula: TiO₂

ⓘ 'Tourmaline'

Formula: AD₃G₆(T₆O₁₈)(BO₃)₃X₃Z

References:

ⓘ Zircon

Formula: Zr(SiO₄)

References:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
ⓘ	Diamond	1.CB.10a	C
Group 4 - Oxides and Hydroxides
ⓘ	Goethite	4.00.	Fe³⁺O(OH)
ⓘ	Magnetite	4.BB.05	Fe²⁺Fe³⁺₂O₄
ⓘ	Hematite	4.CB.05	Fe₂O₃
ⓘ	Ilmenite	4.CB.05	Fe²⁺TiO₃
ⓘ	Perovskite	4.CC.30	CaTiO₃
ⓘ	Quartz	4.DA.05	SiO₂
ⓘ	Opal	4.DA.10	SiO₂ · nH₂O
ⓘ	Rutile	4.DB.05	TiO₂
ⓘ	Anatase	4.DD.05	TiO₂
Group 9 - Silicates
ⓘ	Almandine	9.AD.25	Fe²⁺₃Al₂(SiO₄)₃
ⓘ	Grossular	9.AD.25	Ca₃Al₂(SiO₄)₃
ⓘ	Pyrope	9.AD.25	Mg₃Al₂(SiO₄)₃
ⓘ	Zircon	9.AD.30	Zr(SiO₄)
ⓘ	Kyanite	9.AF.15	Al₂(SiO₄)O
ⓘ	Epidote	9.BG.05a	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
ⓘ	Muscovite var. Illite	9.EC.15	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
ⓘ		9.EC.15	KAl₂(AlSi₃O₁₀)(OH)₂
ⓘ	Kaolinite	9.ED.05	Al₂(Si₂O₅)(OH)₄
Unclassified
ⓘ	'Monazite Group'	-	REE(PO₄)
ⓘ	'Tourmaline'	-	AD₃G₆(T₆O₁₈)(BO₃)₃X₃Z

List of minerals for each chemical element

H	Hydrogen
H	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
H	ⓘ Goethite	Fe³⁺O(OH)
H	ⓘ Muscovite var. Illite	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
H	ⓘ Kaolinite	Al₂(Si₂O₅)(OH)₄
H	ⓘ Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂
H	ⓘ Opal	SiO₂ · nH₂O
B	Boron
B	ⓘ Tourmaline	AD₃G₆(T₆O₁₈)(BO₃)₃X₃Z
C	Carbon
C	ⓘ Diamond	C
O	Oxygen
O	ⓘ Anatase	TiO₂
O	ⓘ Almandine	Fe₃²⁺Al₂(SiO₄)₃
O	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
O	ⓘ Goethite	Fe³⁺O(OH)
O	ⓘ Grossular	Ca₃Al₂(SiO₄)₃
O	ⓘ Hematite	Fe₂O₃
O	ⓘ Muscovite var. Illite	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
O	ⓘ Ilmenite	Fe²⁺TiO₃
O	ⓘ Kaolinite	Al₂(Si₂O₅)(OH)₄
O	ⓘ Kyanite	Al₂(SiO₄)O
O	ⓘ Magnetite	Fe²⁺Fe₂³⁺O₄
O	ⓘ Monazite Group	REE(PO₄)
O	ⓘ Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂
O	ⓘ Opal	SiO₂ · nH₂O
O	ⓘ Perovskite	CaTiO₃
O	ⓘ Pyrope	Mg₃Al₂(SiO₄)₃
O	ⓘ Quartz	SiO₂
O	ⓘ Rutile	TiO₂
O	ⓘ Tourmaline	AD₃G₆(T₆O₁₈)(BO₃)₃X₃Z
O	ⓘ Zircon	Zr(SiO₄)
Mg	Magnesium
Mg	ⓘ Pyrope	Mg₃Al₂(SiO₄)₃
Al	Aluminium
Al	ⓘ Almandine	Fe₃²⁺Al₂(SiO₄)₃
Al	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
Al	ⓘ Grossular	Ca₃Al₂(SiO₄)₃
Al	ⓘ Muscovite var. Illite	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
Al	ⓘ Kaolinite	Al₂(Si₂O₅)(OH)₄
Al	ⓘ Kyanite	Al₂(SiO₄)O
Al	ⓘ Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂
Al	ⓘ Pyrope	Mg₃Al₂(SiO₄)₃
Si	Silicon
Si	ⓘ Almandine	Fe₃²⁺Al₂(SiO₄)₃
Si	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
Si	ⓘ Grossular	Ca₃Al₂(SiO₄)₃
Si	ⓘ Muscovite var. Illite	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
Si	ⓘ Kaolinite	Al₂(Si₂O₅)(OH)₄
Si	ⓘ Kyanite	Al₂(SiO₄)O
Si	ⓘ Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂
Si	ⓘ Opal	SiO₂ · nH₂O
Si	ⓘ Pyrope	Mg₃Al₂(SiO₄)₃
Si	ⓘ Quartz	SiO₂
Si	ⓘ Zircon	Zr(SiO₄)
P	Phosphorus
P	ⓘ Monazite Group	REE(PO₄)
K	Potassium
K	ⓘ Muscovite var. Illite	K_0.65Al_2.0[Al_0.65Si_3.35O₁₀](OH)₂
K	ⓘ Muscovite	KAl₂(AlSi₃O₁₀)(OH)₂
Ca	Calcium
Ca	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
Ca	ⓘ Grossular	Ca₃Al₂(SiO₄)₃
Ca	ⓘ Perovskite	CaTiO₃
Ti	Titanium
Ti	ⓘ Anatase	TiO₂
Ti	ⓘ Ilmenite	Fe²⁺TiO₃
Ti	ⓘ Perovskite	CaTiO₃
Ti	ⓘ Rutile	TiO₂
Fe	Iron
Fe	ⓘ Almandine	Fe₃²⁺Al₂(SiO₄)₃
Fe	ⓘ Epidote	(CaCa)(AlAlFe³⁺)O[Si₂O₇][SiO₄](OH)
Fe	ⓘ Goethite	Fe³⁺O(OH)
Fe	ⓘ Hematite	Fe₂O₃
Fe	ⓘ Ilmenite	Fe²⁺TiO₃
Fe	ⓘ Magnetite	Fe²⁺Fe₂³⁺O₄
Zr	Zirconium
Zr	ⓘ Zircon	Zr(SiO₄)

Other Regions, Features and Areas containing this locality

Brazil

Minas Gerais
- Bagagem River valleyValley
- Coromandel mining districtMining District

South AmericaContinent

South America PlateTectonic Plate

Parana basinBasin
Tocantins ProvinceOrogenic Belt

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

Draper, D. (1911) The diamond bearing deposits of Bagagem and Agua Suja, in the state of Minas Geraes (sic), Brazil. Transactions of the Geological Society of South Africa, 14, 8-19.

Suguio, K., Svisero, D.P., and Filitti, F.W. (1979) Conglomerados polimiticos diamantiferos de idade cretácica de Romaria (MG): um exemplo de sedimentação de leques aluviais. 2nd Simpósio Regional de Geologia Rio Claro, 1, 217-229.

Fleischer, R. (1998) A rift model for the sedimentary diamond deposits of Brazil. Mineralium Deposita, 33 (3) 238-254 doi:10.1007/s001260050144

Grütter, H.S., Gurney, J. J., Menziesc, A.H., and Winter, F. (2004) An updated classification scheme for mantle-derived garnet, for use by diamond explorers. Lithos, 77, 841-857.

Andrade, K.W. and Chaves, M.L.S.C. (2009) Geologia e a redistribuição sedimentar pós-Cretácica dos depósitos diamantíferos da região ao sul de Coromandel (MG). Geonomos, 17(1), 27-36.

Coelho, F.M. (2010) Aspectos geológicos e mineralógicos da mina de diamantes de Romaria, Minas Geras. tese, Universidade de São Paulo, Instituto de Geociêncas.

Andrade, K.W. and Chaves, M.L.S.C. (2011) Geologia e mineralogia do kimberlito Grota do Cedro (Coromandel, MG). Geonomos, 19(1), 39-45.

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Romaria mine, Romaria, Minas Gerais, BraziliRegional Level TypesRomaria mineMine RomariaMunicipality Minas GeraisState BrazilCountry function showexplain() { $("#locexplain").toggle(); if (typeof movemap === "function") movemap(); }

Select Mineral List Type

Mineral List

Detailed Mineral List:

Gallery:

List of minerals arranged by Strunz 10th Edition classification

List of minerals for each chemical element

Other Regions, Features and Areas containing this locality

References

Romaria mine, Romaria, Minas Gerais, Brazil i
Regional Level Types
Romaria mine Mine
Romaria Municipality
Minas Gerais State
Brazil Country