FMF - Friends of Minerals Forum, discussion and message board

[Carles Millan]

To John S. White

Just for you (and the other readers) to see, and for clarity reasons as well, I've posted here a new picture taken from the schorl you were talking about, where the upper termination edges have been enhanced with a blue line.

This specimen is the same that can be seen above at https://www.mineral-forum.com/message-board/viewtopic.php?p=5690#5690

[GneissWare]

Aren't these "rough" terminations either a result of parallel growth or maybe differential etching?

I've seen tourmalines from Pakistan consisting of multiple, very-fine crystals that form what appears to be a single consolidated crystal with a complex termination that looks at a distance, like a single pinacoid termination, sort of like this crystal. Some you have to study quite closely to see the individual crystals.

Tourmaline, like other minerals, also exhibits etching on some faces while being pristine on others. Generally, I wouldn't expect such a sharp termination as this crystal, but in minerals all things seems possible (even the improbable things).

[Carles Millan]

Hi GneissWare!

With a 15x loupe I cannot see any parallel growth. There is perhaps some etching, but my knowledge of this matter is not enough to be sure.

[Carles Millan]

Scheelite, muscovite

Translucent sharp scheelite crystal measuring 21mm on longest edge, on a matrix of muscovite crystals. No damage. Overall size: 70 mm x 50 mm x 30 mm. Weight: 150 g. Ex Lloyd Tate Collection.

Mt Xuebaoding, Pingwu Co., Mianyang Prefecture, Sichuan Province, China.

Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited. Creative Commons Attribution Licence - Some Rights Reserved.

[John S. White]

Thank you Carles, I suspected it was something like that, and I have no idea why this crystal formed the way it did. Another "head scratcher."

[Carles Millan]

Hi John!

You get up really early every day! I hope you don't suffer of insomnia. I do it much later...

Now about the schorl: I'm sure any person wiser than me, probably yourself, just by observing the upper termination with a loupe, would easily be able to find out why the faces are so rough in contrast with the ones forming the prism walls.

[Carles Millan]

Pyrite

Group of octahedral {111} crystals. Overall size: 64 mm x 56 mm. Main crystal: 52 mm tall, 42 mm on edge. Weight: 242 g. Complete all around. Note that each vertex shows what seems to be two small pyritohedral {210} faces (or perhaps rhombododecahedral {110}, very uncommon in pyrite).

If you love the octahedral pyrites as I do please see a similar specimen at https://www.mineral-forum.com/message-board/viewtopic.php?p=2663#2663

Mina Huanzala, Huallanca, Dos de Mayo, Huánuco, Peru.

Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited. Creative Commons Attribution License - Some Rights Reserved.

My Personal Site

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2786M-pyrite1.jpg
Description:	Pyrite Mina Huanzala, Huallanca, Dos de Mayo, Huánuco, Peru 64 mm x 56 mm. Main crystal: 52 mm tall, 42 mm on edge
Viewed:	59020 Time(s)

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2786M-pyrite.jpg
Description:	Pyrite Mina Huanzala, Huallanca, Dos de Mayo, Huánuco, Peru 64 mm x 56 mm. Main crystal: 52 mm tall, 42 mm on edge
Viewed:	59066 Time(s)

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2786M-pyrite2.jpg
Description:	Pyrite Mina Huanzala, Huallanca, Dos de Mayo, Huánuco, Peru 64 mm x 56 mm. Main crystal: 52 mm tall, 42 mm on edge
Viewed:	59097 Time(s)

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2786M-pyrite3.jpg
Description:	Pyrite Mina Huanzala, Huallanca, Dos de Mayo, Huánuco, Peru 64 mm x 56 mm. Main crystal: 52 mm tall, 42 mm on edge
Viewed:	59019 Time(s)

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[Carles Millan]

Fluorite, quartz

Group of green octahedral {111} fluorite crystals with quartz. Overall size: 80 mm x 56 mm x 35 mm. Largest fluorite crystal: 20 mm on edge. Weight: 126 g.

Riemvasmaak, Gordonia District, Namaqualand, Northern Cape Province, South Africa.

Reference: "The Mineralogical Record", vol. 40, #4, July-August 2009, pages 307-324.

Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited. Creative Commons Attribution License - Some Rights Reserved.

[Carles Millan]

Kësterite, mushistonite

Kësterite crystal covered with mushistonite on a matrix with mica. Overall size: 60 mm x 45 mm. Kësterite crystal size: 15 mm wide. Weight: 64 g. Undamaged.

Mt Xuebaoding, Pingwu Co., Mianyang Prefecture, Sichuan Province, China.

Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited. Creative Commons Attribution License - Some Rights Reserved.

[Carles Millan]

Babingtonite, prehnite, quartz

Group of babingtonite crystals on spheroidal prehnite, and quartz. Overall size: 71 mm x 55 mm. Major crystal size: 22 mm on edge. The main crystal is doubly terminated.

Qiaojia, Zhaotong, Yunnan, China.

Photos copyright © Carles Millan. Reproduction allowed as long as the author's name is cited and the image not modified. Creative Commons Attribution Licence - Some Rights Reserved.

[Jon Mommers]

Carles,

That Babingtonite is simply stunning and great contrasting matrix of Prehnite and Quartz.
Congratulations
John

[Carles Millan]

To Jon Mommers:

I'm very glad you like it.

Thank you for your comment.

[Tracy]

The photos are just fine, Carles, and the piece is exquisite. Thanks for sharing your beautiful specimens.

- Tracy

[Carles Millan]

Hi Tracy!

I meant I would like to be able to get better photos from my specimens. But as you already know it's not an easy task. Some of them are especially hard to be shot and it's very frustrating when you're unsuccessful after many tries.

You have a lot of good photos at your section. I especially like this hematite: https://www.mineral-forum.com/message-board/viewtopic.php?p=1092#1092 Please, keep posting.

[parfaitelumiere]

Hi Carles,Seems there is a mistake about the dolomite from Peru,seems the sample on the pics is a Baryte.