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GeneralRose Quartz or not?

30th Mar 2015 17:02 UTCLarry Maltby Expert

This vein from the St. Louis Mine near Calumet, Michigan has puzzled me for some time. It is composed mostly of calcite and massive and also crystalized “pink quartz”. After about 60 years of prowling the Keweenaw, I have never seen anything like this. The question, is this rose quartz? If not, why not? I don’t believe that rose quartz has ever been recorded in the Copper Range. In the attached photos the calcite has been completely removed by leaching in acid. Everything that you see was “submerged” in calcite.

Please let me know what you think.

Larry,

30th Mar 2015 17:48 UTCBob Harman

I'll attempt to answer your question including a photo of an Indiana geode with rosy pink quartz. In my opinion it really depends on your definition of rose quartz, smoky quartz, amethyst quartz and citrine quartz. If your definition includes only color then all rosy pink quartz could be called ROSE QUARTZ. If your definition includes only color, then light thru dark gray quartz could be called SMOKY QUARTZ. If your definition includes only color then all light thru dark purple quartz could be called AMETHYST and so on for CITRINE.

But if your definition of each of the color varieties of quartz includes more than just the color per se, such as mode of formation, atoms of other elements included within the quartz crystals etc etc then the definition of the color variety's name might be a bit more questioned…..especially by purists. That is my humble opinion from one with little true geological knowledge of the subject. BTW that is one interesting specimen and I would call it ROSE QUARTZ! CHEERS…….BOB

30th Mar 2015 17:57 UTCDavid Von Bargen Manager

It might be copper included quartz (also it could be hematite).

30th Mar 2015 20:03 UTCWayne Corwin

Larry

Has it ever been tested that you know of?

30th Mar 2015 20:06 UTCLarry Maltby Expert

Bob,

I see your point. Like you I tend to simplify things if possible. Rose quartz does not seem to have a scientific definition therefor, because this is crystalized and it is the same color as many of the specimens that I have seen that are labeled rose quartz why not call it rose quartz? A purist may say if it is not from a pegmatite it cannot be rose quartz. Another purist may say if it does not have fibers included that are similar to dumortierite it cannot be rose quartz. I doubt that all of the purists agree on a definition. I just noticed that I said “crystalized”. I guess that makes me a purist of sorts. If the specimen was chalcedony of the same color I would not have called it rose quartz.

David,

I think that you may be right when you suggested that the color may be caused by copper. I have attached another photo to show the association with copper.

30th Mar 2015 20:54 UTCReiner Mielke Expert

You can avoid the issue by calling it rose colored quartz.

30th Mar 2015 22:49 UTCOwen Melfyn Lewis

Reiner Mielke Wrote:

-------------------------------------------------------

> You can avoid the issue by calling it rose colored

> quartz.

:)-D

31st Mar 2015 06:25 UTCRock Currier Expert

Was your specimen etched out of calcite?

31st Mar 2015 14:08 UTCLarry Maltby Expert

Wayne,

This pink quartz has not been tested yet. I will send it out soon and post the results. It would be interesting to find out what the coloring agent is.

Rock,

Yes, the calcite has been completely removed from the specimens shown here. I have other specimens that are partially etched and still others that are not etched at all. In some areas the vein is 3 to 4 inches wide and about 50% calcite and 50% pink quartz. I am almost done with a Mindat article on this mine and I hope to publish this summer. I will cover the vein in more detail in the article. I think that the calcite formed first and the quartz later. This sequence is common in the Lake Shore Traps. I have several specimens where vein chalcedony/agate has large casts of perfect calcite crystals. What is unique here is that the quartz sometimes terminates. I have not seen that elsewhere.

I could warm up to the idea of calling the terminated crystals rose quartz but it looks like it would be forever controversial. For the sake of the article I will just use the term pink quartz.

31st Mar 2015 16:22 UTCGeorg Graf

Hi Larry,

according to Rykart, Rudolf: Quarz-Monographie; Thun, Ott, 1989 (in German) exist two rosa coloured Quartz varieties:

1. SiO2 substituted by AlOP and influenced by radiation; found in hydrothermal environment.

2. SiO2 containing traced of Ti3+; found in pegmatitic environment.

Best wishes! Gg

31st Mar 2015 16:25 UTCGeorg Graf

Hi again Larry,

nice specimens; thanks for sharing!

Georg

31st Mar 2015 17:51 UTCOwen Melfyn Lewis

Georg Graf Wrote:

-------------------------------------------------------

> Hi Larry,

>

> according to Rykart, Rudolf: Quarz-Monographie;

> Thun, Ott, 1989 (in German) exist two rosa

> coloured Quartz varieties:

> 1. SiO2 substituted by AlOP and influenced by

> radiation; found in hydrothermal environment.

> 2. SiO2 containing traced of Ti3+; found in

> pegmatitic environment.

>

> Best wishes! Gg

Yes, very pretty specimen :-)

Nassau (1991) concurs, adding as follows:

- Your 2 is Ti3+ -> Ti5+ charge transfer, the colour being unstable when exposed to white light. Frondel reports the fading as 'slight, if any'. Another source (Bauer) giver the fading as pronounced and rapid. In turn, this divergence suggests that Frondel and Bauer were examining samples with different chromophore(s) present.

- Your 1. is a radiation-induced Al3+ -> P5+ charge transfer (stable in white light).

- He adds colourless quartz with inclusions of pink dumortierite as a third rose-coloured quartz.

1st Apr 2015 13:05 UTCLarry Maltby Expert

Georg and Owen,

Thanks for the references. I found another professional reference that cites rose quartz from a hydrothermal environment. The St. Louis Mine worked the Copper City Flow which contains highly altered basalt from many pulses of hydrothermal activity. It will be interesting to see if the analysis can identify the impurities that may be responsible for the color.

2nd Apr 2015 21:31 UTCRock Currier Expert

It looks to me like the base of the specimen might be chalcedony that changes into rose colored quartz in the crystals. There is no such thing as a rose quartz police so you could probably call it rose quartz if you wanted to. It used to be that the only know crystals of rose quartz were from Maine and it was given the name of rose quartz because it had that color. They didn't know what caused the coloration for sure. Now it appears many years later that the color in many rose quartz specimens is caused by a dumorterite like nano mineral. Considerable data has been collected about it, but as far as I know it has not yet been enough for the IMA to give its blessing to a particular name. So sending your stuff out for analysis will not give you a name to call it. Its not something that can be determined by normal analysis like x-ray or microprobe. On such a small sample I'm not sure if it could be determined what the coloring agent is but if it could be I would imagine the cost of the analysis would be into the many thousands of dollars and even then you might end up with the answer that it was caused by a nano mineral that does not yet have a name.

3rd Apr 2015 13:26 UTCLarry Maltby Expert

Thanks for he comment, Rock.

I see your point. I cannot spend the funds required to determine exactly what the coloring agent of this quartz is. I thought that I would do some simple inexpensive analysis looking for clues. If copper shows up as an impurity that would be a clue. If boron shows up as an impurity that would be another clue. The chemistry of dumortierite contains boron. This is, of course, a long shot and the results would be inconclusive but we would at least verify that the massive pink mineral is quartz. The St. Louis has surprised us before. The bright yellow pumpellyite has been confirmed with analysis and the bright yellow epidote from this locality has also been confirmed. If we write enough about this location perhaps a student at Michigan Tech working on an advanced degree will get involved. I would be happy to supply specimens for the study.

Larry,

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