Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects
Autor(a) principal: | |
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Data de Publicação: | 2014 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | REM. Revista Escola de Minas (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0370-44672014000200005 |
Resumo: | A representative set of diamonds from the Borrachudo River (114 stones) was described for the first time as to their physical characteristics, among them weight, morphology, dissolution figures, and abrasion. Most samples are low in weight (~51% less than 0.30 ct) and only ~3.5% are above 3.0 ct. However, considering the total weight, ~47% of it is concentrated in the range above 3 ct. On the other hand, there even occur diamonds with dozen of carats. The most common crystallographic forms are originated from the octahedral form by dissolution, although irregular shapes like chips and flats also occur. The diamonds show differences in form compared to their weight ranges; those up to 0.30 ct have various shapes; in the range of 0.31 to 1 ct the most common are octahedral forms and their descendants; and in stones larger than 1 ct chips and flats predominate. The general habitus of the crystals, identified by their final tetrahexahedroid shapes, chips and flats, corroborated by the dissolution figures, indicate that the diamond were submitted to strong dissolution in a magmatic environment. Residual hillocks and holes represent the final stage of dissolution. The study indicates that the abrasion by the fluvial transport was not expressive enough to cause mechanical wear, thus ca. 97% shows no sign of wear. This fact suggests a proximal source for most of these diamonds. |
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Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspectsDiamondBorrachudo RiverSão Francisco BasinA representative set of diamonds from the Borrachudo River (114 stones) was described for the first time as to their physical characteristics, among them weight, morphology, dissolution figures, and abrasion. Most samples are low in weight (~51% less than 0.30 ct) and only ~3.5% are above 3.0 ct. However, considering the total weight, ~47% of it is concentrated in the range above 3 ct. On the other hand, there even occur diamonds with dozen of carats. The most common crystallographic forms are originated from the octahedral form by dissolution, although irregular shapes like chips and flats also occur. The diamonds show differences in form compared to their weight ranges; those up to 0.30 ct have various shapes; in the range of 0.31 to 1 ct the most common are octahedral forms and their descendants; and in stones larger than 1 ct chips and flats predominate. The general habitus of the crystals, identified by their final tetrahexahedroid shapes, chips and flats, corroborated by the dissolution figures, indicate that the diamond were submitted to strong dissolution in a magmatic environment. Residual hillocks and holes represent the final stage of dissolution. The study indicates that the abrasion by the fluvial transport was not expressive enough to cause mechanical wear, thus ca. 97% shows no sign of wear. This fact suggests a proximal source for most of these diamonds.Escola de Minas2014-06-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0370-44672014000200005Rem: Revista Escola de Minas v.67 n.2 2014reponame:REM. Revista Escola de Minas (Online)instname:Escola de Minasinstacron:ESCOLA DE MINAS10.1590/S0370-44672014000200005info:eu-repo/semantics/openAccessBorges,Luis Alberto de DeusChaves,Mario Luiz de Sá CarneiroKarfunkel,Joachimeng2014-07-25T00:00:00Zoai:scielo:S0370-44672014000200005Revistahttp://www.scielo.br/remhttps://old.scielo.br/oai/scielo-oai.phpeditor@rem.com.br1807-03530370-4467opendoar:2014-07-25T00:00REM. Revista Escola de Minas (Online) - Escola de Minasfalse |
dc.title.none.fl_str_mv |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
title |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
spellingShingle |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects Borges,Luis Alberto de Deus Diamond Borrachudo River São Francisco Basin |
title_short |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
title_full |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
title_fullStr |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
title_full_unstemmed |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
title_sort |
Diamonds from Borrachudo river, São Francisco basin (Tiros, MG): morphologic and dissolution aspects |
author |
Borges,Luis Alberto de Deus |
author_facet |
Borges,Luis Alberto de Deus Chaves,Mario Luiz de Sá Carneiro Karfunkel,Joachim |
author_role |
author |
author2 |
Chaves,Mario Luiz de Sá Carneiro Karfunkel,Joachim |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Borges,Luis Alberto de Deus Chaves,Mario Luiz de Sá Carneiro Karfunkel,Joachim |
dc.subject.por.fl_str_mv |
Diamond Borrachudo River São Francisco Basin |
topic |
Diamond Borrachudo River São Francisco Basin |
description |
A representative set of diamonds from the Borrachudo River (114 stones) was described for the first time as to their physical characteristics, among them weight, morphology, dissolution figures, and abrasion. Most samples are low in weight (~51% less than 0.30 ct) and only ~3.5% are above 3.0 ct. However, considering the total weight, ~47% of it is concentrated in the range above 3 ct. On the other hand, there even occur diamonds with dozen of carats. The most common crystallographic forms are originated from the octahedral form by dissolution, although irregular shapes like chips and flats also occur. The diamonds show differences in form compared to their weight ranges; those up to 0.30 ct have various shapes; in the range of 0.31 to 1 ct the most common are octahedral forms and their descendants; and in stones larger than 1 ct chips and flats predominate. The general habitus of the crystals, identified by their final tetrahexahedroid shapes, chips and flats, corroborated by the dissolution figures, indicate that the diamond were submitted to strong dissolution in a magmatic environment. Residual hillocks and holes represent the final stage of dissolution. The study indicates that the abrasion by the fluvial transport was not expressive enough to cause mechanical wear, thus ca. 97% shows no sign of wear. This fact suggests a proximal source for most of these diamonds. |
publishDate |
2014 |
dc.date.none.fl_str_mv |
2014-06-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0370-44672014000200005 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0370-44672014000200005 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0370-44672014000200005 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Escola de Minas |
publisher.none.fl_str_mv |
Escola de Minas |
dc.source.none.fl_str_mv |
Rem: Revista Escola de Minas v.67 n.2 2014 reponame:REM. Revista Escola de Minas (Online) instname:Escola de Minas instacron:ESCOLA DE MINAS |
instname_str |
Escola de Minas |
instacron_str |
ESCOLA DE MINAS |
institution |
ESCOLA DE MINAS |
reponame_str |
REM. Revista Escola de Minas (Online) |
collection |
REM. Revista Escola de Minas (Online) |
repository.name.fl_str_mv |
REM. Revista Escola de Minas (Online) - Escola de Minas |
repository.mail.fl_str_mv |
editor@rem.com.br |
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1754122198698688512 |