@article{PAR00003290,
  title = {{R}ubies and sapphires from winza, central {T}anzania},
  author = {{S}chwarz, {D}. and {P}ardieu, {V}. and {S}aul, {J}. {M}. and {S}chmetzer, {K}. and {L}aurs, {B}. {M}. and {G}iuliani, {G}aston and {K}lemm, {L}. and {M}alsy, {A}. {K}. and {E}rel, {E}. and {H}auzenberger, {C}. and {D}u {T}oit, {G}. and {F}allick, {A}. {E}. and {O}hnenstetter, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ince late 2007, rubies and sapphires have been mined by hand methods from both eluvial and primary deposits at {W}inza in central {T}anzania. {T}he gem corundum is related to "dikes" of amphibolitic rocks that belong to the {P}aleoproterozoic {U}sagaran {B}elt. {B}ased on crystal morphology, {W}inza corundum is subdivided into two types: prismatic-tabular-rhombohedral and dipyramidal. in general, medium red and dark (orangy) red top-quality rubies are rhombohedral. {P}inkish red and purplish red rubies, as well as pink, purple, and blue (often strongly color zoned) sapphires are, for the most part, dipyramidal. {T}he top-quality rubies are characterized by a distinct assemblage of long tube-, fiber-, needle-, or hair-like inclusions containing an orange-brown material (most likely limonite). {T}he lower-quality material generally contains a larger amount of solid inclusions (mostly amphibole crystals), fissures, and growth features. {U}nique to corundum from this locality are bluish violet color zones oriented parallel to the prism and basal pinacoid, and occasionally also parallel to rhombohedral and dipyramidal faces. {T}he relatively high {F}e content of {W}inza rubies separates them from most other natural and almost all synthetic counterparts.},
  keywords = {},
  booktitle = {},
  journal = {{G}ems and {G}emology},
  volume = {44},
  numero = {4},
  pages = {322--347},
  ISSN = {0016-626{X}},
  year = {2008},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00003290},
}