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Pedro Alves' Photo Gallery

WYK-UM4Descloizite

Herdade de Vila Ruiva Mine, Sobral da Adiça, Moura, Beja, Portugal

Field of View: 3.76 mm

Group of deep brown descloizite crystals. In this case the aspect is closer to that observed in the Preguiça Mine. We can observe the forms {001}, {110}, {111} and {301}.

EDS analyzed, V:As ratio ~5:1.
Copyright: © Pedro Alves      Photo ID: 964352     Uploaded by: Pedro Alves   View Count: 23   Approval status: Public galleries    Type: Photo - 6240 x 4160 pixels (26.0 Mpix)

5CW-NG5Descloizite

Herdade de Vila Ruiva Mine, Sobral da Adiça, Moura, Beja, Portugal

Field of View: 3.19 mm

Group of golden yellow descloizite crystals.
EDS analyzed.

Note:
several specimens from this location where analyzed, with the intention of characterizing chemically the different aspects (color, morphology and the combination of the two). Contrary to what is observed in the neighboring mine (Preguiça Mine), the descloizite from Herdade de Vila Ruiva tends to be more clear in color (from pale yellow-orange to golden brown) and the crystals are elongated. More rarely we can found dark brown crystals with a weak development of the prism(s).
There is no direct correlation with the V:As content and the morphology, but the lowest V:As ratio (~2:1) was observed in the individuals with clearer tones (like those in this picture). Said that, cataloging the specimens from this mine as arsenodescloizite without appropriate analysis, is not recommended. As stated above, in a universe of almost 30 samples, which are intended to be representative of the different forms of occurrence, the lowest V:As ratio observed is about 2:1, far from being As dominant (thus arsenodescloizite).
Copyright: © Pedro Alves      Photo ID: 964350     Uploaded by: Pedro Alves   View Count: 38   Approval status: Public galleries    Type: Photo - 5291 x 4040 pixels (21.4 Mpix)

FPC-NQ1Zirconolite, Sanidine

Pumice quarry, Ribeira Grande, São Miguel Island, Azores, Portugal

Field of View: 1.58 mm

Different aspects of zirconolite crystals: Elongated deep brown, thinner golden brown and flat tabular. In the left side of the picture we can see the tip of sanidine crystal.

Copyright: © Pedro Alves      Photo ID: 964225     Uploaded by: Pedro Alves   View Count: 38   Approval status: Public galleries    Type: Photo - 5244 x 3968 pixels (20.8 Mpix)

U9G-7NRCyanotrichite, Brochantite

Bugalho Mine, São Brás dos Matos, Alandroal, Évora, Portugal

Field of View: 7.52 mm

'Electric blue' cyanotrichite 'urchins' associated to deep green brochantite crystals.
Both EDS checked.

NOTE:
Cyanotrichite and camérolaite are not distinguishable by visual examination (even if cyanotrichite, at this locality, is deeper in color).
The cyanotrichite from this specimen is Sb free.
Copyright: © Pedro Alves      Photo ID: 958764     Uploaded by: Pedro Alves   View Count: 34   Approval status: Public galleries    Type: Photo - 6240 x 4160 pixels (26.0 Mpix)

55E-WKNBismuth, Bismutite

Fonte da Cal Mine, Bendada Mines, Bendada, Sabugal, Guarda, Portugal

Field of View: 3.76 mm

Native bismuth grain with his typical tarnish.
The yellow massive material is a mixture of bismutite and anglesite.

All EDS analyzed.
Copyright: © Pedro Alves      Photo ID: 949431     Uploaded by: Pedro Alves   View Count: 41   Approval status: Public galleries    Type: Photo - 6240 x 4160 pixels (26.0 Mpix)

M1L-MM7Linarite

Olgas Mine, Castelo Branco, Mogadouro, Bragança, Portugal

Field of View: 7.52 mm

Flat tabular linarite crystal, relatively large for the locality (~5 mm), associated to malachite.
Copyright: © Pedro Alves      Photo ID: 949428     Uploaded by: Pedro Alves   View Count: 37   Approval status: Public galleries    Type: Photo - 6240 x 4160 pixels (26.0 Mpix)

D8A-J1AChalcopyrite, Sphalerite

Moinho deposit, Aljustrel Mine, Aljustrel, Aljustrel, Beja, Portugal

Field of View: 5.43 mm

Chalcopyrite crystals, some of them slightly oxidized (blue and orange-red iridescence).
The matrix (pyrite) is also oxidized, due to post mining water percolation along the fissures. In the oldest works, caused by the same phenomena, gypsum can also be found.
We can observe a deep brown sphalerite crystal attached to the 'triangular' chalcopyrite. The color is due to the Fe content, usually between 3,0% and 6,5%).

Note: Galena, not in the picture, is also present. This is the typical association observed in the more fractured (tectonized) copper rich massive sulphides from the Moinho deposit, Aljustrel.
Copyright: © Pedro Alves      Photo ID: 947628     Uploaded by: Pedro Alves   View Count: 171   Approval status: Public galleries    Type: Photo - 4472 x 3248 pixels (14.5 Mpix)

V8H-165Manganoeudialyte

Água de Pau Volcano, Ribeira Grande, São Miguel Island, Azores, Portugal

Field of View: 2.29 mm

Golden orange manganoeudialyte crystal on sanidine.
EDS analyzed.

Mindat.org Photo of the Day - 23rd Mar 2019
Copyright: © Pedro Alves      Photo ID: 943900     Uploaded by: Pedro Alves   View Count: 393   Approval status: Public galleries    Type: Photo - 3776 x 3136 pixels (11.8 Mpix)

9HR-LA6Scheelite, Quartz

Vinheiros Mine, Souto Maior, Sabrosa, Vila Real, Portugal

Field of View: 52 mm
Largest Crystal Size: 8 mm

Floater specimen.
Brown scheelite with etching patterns (clearer areas) on a cluster of bi-terminated quartz crystals.
Copyright: © Pedro Alves      Photo ID: 942600     Uploaded by: Pedro Alves   View Count: 49   Approval status: Public galleries    Type: Photo - 3414 x 2698 pixels (9.2 Mpix)

4J0-DW9Greifensteinite

Fonte da Cal Mine, Bendada Mines, Bendada, Sabugal, Guarda, Portugal

Field of View: 0.95 mm

Group of golden brown greifensteinite crystals on skeletal quartz.
While roscherite (from Fonte da Cal Mine) is Fe rich greifensteinite is virtually Mn free, at least in the analyzed samples.
XRD and EDS characterized.

Mindat.org Photo of the Day - 1st Apr 2019
Copyright: © Pedro Alves      Photo ID: 942008     Uploaded by: Pedro Alves   View Count: 466   Approval status: Public galleries    Type: Photo - 3112 x 2536 pixels (7.9 Mpix)
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