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[Tracy]

Below are some photos of two DT crystals which I recently acquired, both 3.5-4 cm long. The first, from the Wendula Lasserre Collection, is listed in the seller's label (not shown) as being from Sauerland, North Rhine-Westphalia, Germany, and the Lasserre label indicates it came from Siegerland, which matches the Sauerland locality. An older label is also shown but I can't decipher it (I posted it in case anybody else can - I think the last word might be "Westphalia" but can't get any further). I was told that this crystal could be one of the "Suttrop" quartzes, as the listed locality is close to the quarry where the Suttrop quartzes were found, but since this can't be confirmed I'll just call it "Suttrop-type."

Lower in the photo is the second crystal, which according to the seller's label comes from Cornwall, England. I have no further information on it. It seems to have a strong resemblance to the German crystal, and I am wondering whether "Suttrop-type" quartzes have also been found in England, or is this label possibly incorrect? These are milky quartz crystals and in theory could be found almost anywhere. However, the resemblance is really striking so I am wondering whether it would also qualify as "Suttrop-type," or for that matter whether it could be a "Suttrop" quartz. Can anyone shed some light?

Thanks...

- Tracy

[Montanpark]

Hi Tracy,
this is IMHO for sure german 'Suttrop' habit biterminated quartz, the old label states westphalia which is correct for the Sauerland occurrence(s) .. could you post a close up of the old label as i can´t read the word before westphalia well. It reads like Sundwig which would be a merely correct locale for the classics as those quartzes come from devonian limestones and were more abundant as some descriptions at mindat may implicate. Siegerland is also wrong, IF it is Sauerland which is a different region.

Although quartzes of that kind could come from a lot of places the old label and the habit is a strong clue.. the newer english label is clearly wrong IMO.
cheers
Roger

[John S. White]

Tracy:

It is always possible for a habit regarded as typical for one locality to be mimiced somewhere else but I would bet the farm that your "Cornwall" label is incorrect and that the crystal is from Suttrop, or very closeby. These crystals are true classics and are about as distinctive as any that I can think of. I have an identical one in my single crystal collection.

[Amir Akhavan]

Suttrop-type quartz are found in Devonian limestones in a narrow stripe about 100km long along the northern border of the Sauerland, so they do not have to come exactly from Suttrop/Warstein. Meanwhile it's difficult to find well-formed single crystals in Suttrop. Lot's of them come from nearby Kallenhardt (just a few km away).

Their formation is probably linked to rising hydrothermal waters from (possibly submarine) volcanism that occured in a narrow stripe a few kilometers south.
There are similar geological settings in the southern Sauerland/Siegerland, so while I'm not very familiar with the geology, the Siegerland and the northern Westerwald are an option. I think similar crystals have been found in Devonian limestone of the Westerwald at Medenbach, near Dillenburg, Hessen, I'm not sure, though.
(It can be difficult to figure out what regions "Westerwald", "Siegerland", "Sauerland" etc refer too. I live here and still have to look it up sometimes...)

I remember a post in some forum a long time ago, where someone from Kentucky or Tennessee was asking something about aggregates of double-terminated milky white quartzes found in karst caves in limestone. Nobody seemed to know anything about them - they were just too "ugly" ;-)
But they looked just as some of those aggregates that frequently accumulate along small dissolved karst cavities and in karst dolines in Suttrop, Bleiwäsche, Kallenhardt and other places.
So, as John said, Suttrop-type quartz might occur at other localities.

Cornwall sounds unlikely, though.

[Amir Akhavan]

Might be "Sundwig, Westfalen".
Sundwig lies within the forementioned "quartz belt" at the northern border of the Sauerland, it is now part of the town of Hemer, Nordrhein-Westfalen ("Northrhine-Westphalia")
I'll try to find out if it is a possible locality.

[Amir Akhavan]

Mineralienatlas.de mentions double-terminated yellow quartz crystals from the "Felsenmeer" ("Sea of Boulders" or "Sea of Rocks") at Sundwig, Hemer. The locality is now a nature preserve.
So it could be from there.

[renpagan]

I remember reading somewhere that the milky white colorof the Suttrop quartz is due to inclusions of anhydrite. Can anybody confirm this?

[Amir Akhavan]

Yes, but most of the anhydrite and selenite got dissolved.
Suttrop-type quartzes have a low specific density because the fluid and gas inclusions can consume up to 10% of the volume.
(a deception package, so to say)

[Tracy]

Thanks all for your responses. Im delighted to read that I'm not the only one who thought "Cornwall" was a bit strange, and am happy to own 2 of these quartzes. Some might find them ugly, but I think they're neat.

Roger, a close-up photo of the label is attached. Too bad there is a heavy crease down the middle. I think Amir's guess of Sundwig, Westfalen is correct. What then would the correct locality be - Sundwig/Hemer, Sauerland, North Rhine-Westphalia?

- Tracy

ps interesting information about low specific gravity...

[Montanpark]

Hi Tracy, all,
the label is clearly Sundwig. Amir also pointed out how those 'Suttrop' quartzes occur - they are bound to the devonian limestones of that region, being epigenetic formations due to hydrothermal processes AFAIR. The 'classic' Siegerland area hasn´t those limestones. There, devonian shales, slates, sand- siltstones and quartzitic sandstones are dominant which host the vein type ore deposits that made the Siegerland famous in the world for its minerals. If your samples are from Germany (which i do not doubt at all) then they are from the Sauerland limestone 'belt'. Sundwig / Hemer is supposed to be correct.

The label says: Quarz -x, beiderseitig ausgebildet, Sundwig, Westfalen

I hope you all had a good start into 2010,

cheers
Roger

[Tracy]

Thanks Roger! I assume that "beiderseitig ausgebildet" means something like "biterminated euhedral?" Y! Babel Fish translated it as "mutually trained" but I got some clues from general Web surfing...

- Tracy

[Montanpark]

Tracy,
beiderseitig ausgebildet means developed on both sides if translated straightly ... which means biterminated in this case of course. :-) .. you are right.

cheers
Roger