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Identity HelpDundas, Ontario locality help?

19th Dec 2016 19:41 UTCJoshua Chambers

Hi all

This specimen was bought as coming from Dundas, Ontario, Canada. It is marcasite on quartz with rutile.

Any ideas as to where it might come from? There is only one mineral listed from Dundas, and that's calcite. Plus, the rutile found in Canada looks nothing like the rutile on this specimen.

I know the picture aren't great, so if you need better quailty photos I can get them :-)

Thanks

Josh

19th Dec 2016 19:58 UTCRichard Gunter Expert

Hi Josh:

Are the twinned crystals in your third photo metallic? Marcasite in the Dundas area can occur as twinned aggregates. Some resemble old-style TV antennae.

19th Dec 2016 20:09 UTCUwe Kolitsch Manager

Third photo shows sagenite, possibly pseudomorphous after ilmenite.

Can't see any marcasite.

19th Dec 2016 20:11 UTCJoshua Chambers

W. Richard. No they are not metallic. I don't really know how to describe the lustre, but they do look very much like straw:-D. It looks like they were once included in the calcite, as there are indentations in the calcite showing this twinning. They also include the majority of the specimen on micro level. This is slightly visible in the top right of the marcasite aggregate

Uwe. The marcasite is meant to be the 2nd picture. I'm honestly not very good with visually IDing marcasite, as I haven't come across it much. I do agree with the sagenite though.:)-D. I'll have a look at ilmenite Ps. quick

Thanks

Josh

19th Dec 2016 20:14 UTCReiner Mielke Expert

The matrix looks like quartz, I see no cleavage. Can you confirm that it is calcite. Besides there is no white massive calcite at Dundas it is all some shade of amber so I doubt if it is from Dundas.

19th Dec 2016 20:19 UTCJoshua Chambers

I saw a pearly section of the matrix, so presumed calcite (due to the pearly cleavage), but double checking, IT IS QUARTZ.

Thanks

Josh

19th Dec 2016 20:20 UTCUwe Kolitsch Manager

The 2nd picture looked like dark chlorite to me (check hardness).

19th Dec 2016 20:24 UTCReiner Mielke Expert

There is no quartz like that at Dundas so it cannot be from there.

19th Dec 2016 20:40 UTCJoshua Chambers

Uwe. No scratch on my fingernail and very crumbly. Also, looking at it closer, the material on the quartz resembles phyllite/schist quite closely. Therefore, most probably chlorite.

Reiner. Ok, thankyou. Guess this is a bit of a 'dud' specimen then:-D. Locality wrong and minerals wrong, NICE!!:-D

Thanks everyone

Josh

20th Dec 2016 07:06 UTCTim Jokela Jr

Interesting twinning, but I echo Reiner's comments.

No rutile at Dundas, no white quartz like that.

20th Dec 2016 09:34 UTCDale Foster Manager

Josh,

I wouldn't give it up as a dud just yet.

The association of white quartz with that golden reticulated rutile and possible chlorite bears a striking resemblance to material from Lanterdan Quarry, Tintagel, Cornwall.

Go check out the pictures: Lanterdan Quarry Rutile

20th Dec 2016 11:29 UTCJoshua Chambers

Dale, you are right; thank you for letting me know. I may mark this locality down with a question mark. The fact that it is an old slate quarry makes sense also. Although the rock on mine looks slightly higher grade, it's close enough.

Thanks

Josh

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