I have been puzzling over a mineral which was found in the Dundas Quarry (North Section) for a while. I picked up a large rock ~80 pounds, and smashed it into smaller bits roughly 5 years ago. The rock was heavily oxidized brown and contained numerous Galena cubes, Calcite crystals, and what appears to be spherical Sphalerite crystal growths around a yellow mineral (possibly sulphur). Sphalerite is also noted on the specimen. Then there is this mineral, which is much smaller than 1 mm, so scratching it would be impossible. It does not fluoresce under short or long wave UV, and forms tapering crystals with hexagonal cross-section. It is red to brown, and also yellow to orange. as shown in the attached photos. I was leaning towards Wurtzite as... 1) Sphalerite and Wurtzite are of the same formula, and Sphalerite is quite common in this quarry. 2) The colour and shape are very similar to that of specimens of Wurtzite in the MINDAT gallery, 3) Some of the crystals are on the outside of the spheres have these crystals attached to the Sphalerite balls, which would be fitting with a collophorm texture (checking my textbooks from back in my geolab days), which are Sphalerite with Wurtzite and Sulphur. In the viscinity of the mystery crystals are Galena cubes as well as Dolomite crystals. Any thoughts would be greatly appreciated. http://www.mindat.org/forum.php?read,105,236364,236364#msg-236364 Wed, 19 Jun 2013 02:21:08 +0000 Phorum 5.2.15a http://www.mindat.org/forum.php?read,105,236364,240722#msg-240722 http://www.mindat.org/forum.php?read,105,236364,240722#msg-240722 Reiner Mielke Localities Mon, 07 Nov 2011 21:14:58 +0000 http://www.mindat.org/forum.php?read,105,236364,240670#msg-240670 http://www.mindat.org/forum.php?read,105,236364,240670#msg-240670
Thanks for the input. Just need some clarification.

The Chemical Analysis indicates Sphalerite or Wurtzite, but the crystal shape is clearly not Sphalerite (6 sided and tapering). Would this then indicate Wurtzite without the XRD as Sphalerite does not do this?

If not, what else could it be?

Andy Haighton,
Brampton, Ontario]]> Andrew Haighton Localities Mon, 07 Nov 2011 15:33:26 +0000 http://www.mindat.org/forum.php?read,105,236364,240124#msg-240124 http://www.mindat.org/forum.php?read,105,236364,240124#msg-240124 Reiner Mielke Localities Wed, 02 Nov 2011 18:56:01 +0000 http://www.mindat.org/forum.php?read,105,236364,240107#msg-240107 http://www.mindat.org/forum.php?read,105,236364,240107#msg-240107
The crystals have been sent in for analysis (attached). The crystals sent in were described as "Long, thin with smooth faces, but different from Sphalerite". The Fe spike is in excess of 8% I am told, though Wurtzite is up to 8%.

I am unfamiliar to this analysis, so I put it out ... What are these crystals, Wurtzite? What ever we come up with, I will set up in Mindat.

Thanks

Andy Haighton,
Brampton, Ontario.]]> Andrew Haighton Localities Wed, 02 Nov 2011 14:15:46 +0000 http://www.mindat.org/forum.php?read,105,236364,236446#msg-236446 http://www.mindat.org/forum.php?read,105,236364,236446#msg-236446
I had been puzzling over this one for a while. There was no record of Wurtzite at this quarry, but all the signs pointed that way. It's always good when your gut feeling seems to be right. That being said, I have been in contact to a collector in the states who would get it analyzed. Never hurts to be 100% sure.(tu)

Thanks.

Andy]]> Andrew Haighton Localities Tue, 27 Sep 2011 17:18:38 +0000 http://www.mindat.org/forum.php?read,105,236364,236444#msg-236444 http://www.mindat.org/forum.php?read,105,236364,236444#msg-236444 Uwe Kolitsch Localities Tue, 27 Sep 2011 17:01:27 +0000 http://www.mindat.org/forum.php?read,105,236364,236376#msg-236376 http://www.mindat.org/forum.php?read,105,236364,236376#msg-236376
I have to admit, Greenockite was another thought I had, though, how would you determine if it was one or the other. The association with the Galena, and the fact that it in oxidized rock (dolomitic limestone hostrock, with occasional shaley zones predominantly in this quarry) lead me to believe that the crystals may be more than just Sphalerite. Oh, and the crystal form doesn't conform to anything else I have seen there.

Andy]]> Andrew Haighton Localities Mon, 26 Sep 2011 15:45:35 +0000 http://www.mindat.org/forum.php?read,105,236364,236370#msg-236370 http://www.mindat.org/forum.php?read,105,236364,236370#msg-236370 I am not familiar with the occurrence, but beside wurtzite wich is a good guess, your description (red or yellow hexagons stacked in inverse pyramids) and the paragenesis could also fit greenockite
Greetings from Belgium
Alain]]> HANSON Alain Localities Mon, 26 Sep 2011 14:30:19 +0000 http://www.mindat.org/forum.php?read,105,236364,236364#msg-236364 http://www.mindat.org/forum.php?read,105,236364,236364#msg-236364
Then there is this mineral, which is much smaller than 1 mm, so scratching it would be impossible. It does not fluoresce under short or long wave UV, and forms tapering crystals with hexagonal cross-section. It is red to brown, and also yellow to orange. as shown in the attached photos.

I was leaning towards Wurtzite as...

1) Sphalerite and Wurtzite are of the same formula, and Sphalerite is quite common in this quarry.
2) The colour and shape are very similar to that of specimens of Wurtzite in the MINDAT gallery,
3) Some of the crystals are on the outside of the spheres have these crystals attached to the Sphalerite balls, which would be fitting with a collophorm texture (checking my textbooks from back in my geolab days), which are Sphalerite with Wurtzite and Sulphur.

In the viscinity of the mystery crystals are Galena cubes as well as Dolomite crystals.
Any thoughts would be greatly appreciated.]]> Andrew Haighton Localities Mon, 26 Sep 2011 13:16:40 +0000