FMF - Friends of Minerals Forum, discussion and message board

[lluis]

Dear Mr. Sampson-White

Indeed interesting!
I normally do not like polished surfaces, but if it the only way to see inside a crystal, what could I do? (not to say cut gems..... At the end, they are cut from chunks of material, the rest of crystal being discarded because it is not so gemmy....)

Very nice photos and very nice specimen. The last I would think to find inside a quartz!

Thanks again for sharing!

With best wishes

Lluís

P.D.: I live really far from USA. If not, I fear that you will have a recurrent visitor to your home (well, collection :-) )
If you come to Spain, you are invited, of course.
Not a bad cook.... :-)
And my wife, a far better cicerone than I

[Cesar M. Salvan]

I think that Internet is a good tool: permit to share things that, without our technology, usually remain hidden to our eyes, in the place where they are deposited.

Truly connoisseurs as well as professionals in the field that share scientific work with collecting (usually a rare combination, at least here...) are usually reluctant to share their "personal mineralogical treasures" with the community, I guess by a variety of reasons. But, where people of great stature, as J.S. White, take the time necessary to share his specimens, it could be an inspiration for all the collectors.

For example, I am not a quartz collector, but your specimens goes beyond. I am particularly impressed by the apatite crystals in quartz you showed in last post. The use of polished sections or thin sections is not usually the focus of mineral collectors, but I think is just another way of specimen preparation, may be deeper than simple stacking in perky boxes or so, but is very useful to appreciate certain species or interesting features. As always, as deeper your knowledge, stronger your capacity to savor things that usually are out of reach of less educated rockhounds. when we see collections of very educated individuals, we quickly see that price or size of specimens is not determinant. On the contrary, oddities, personal history and scientific interest is the driving force. Please, Mr. White, correct me if I am wrong.

And this is why we must acknowledge the effort to share from John S. White.

[Jordi Fabre]

I split this topic, creating a new thread named: "Too much of the same thing" ( https://www.mineral-forum.com/message-board/viewtopic.php?p=5465#5465 )

As the photo of this Chinese Quartz was related with the other topic I copied it below, in order to keep coherent this topic of John S. White collection.

Jordi

[John S. White]

Two more of my included quartzes. Sorry Jordi, they are polished, otherwise we would not be able to see the inclusions. I do not know what the inclusions are. They both are from Minas Gerais, Brazil, and the photos are by Jeff Scovil.

The first one is about 8 cm tall and the other is 6 cm.

[John S. White]

This is probably the largest specimen in my collection, it measures 15 cm across and is from Rio Grande do Sul, Brazil. I acquired this piece because of the cristobalite incusions, which I first became aware of when I was at the Smithsonian and X-rayed one of these. In the close-up you will notice that the cristobalites are elongated and tubular looking.

[parfaitelumiere]

second quartz is really a killer specimen,like a fireworks...;)

[Carles Millan]

Hi John!

I must congratulate you for the excellent article "John S. White, Jr. and his Single Crystal Collection", by Thomas P. Moore, published in The Mineralogical Record, #40/3, about your professional life and minerals collection. I've got the issue this very afternoon and am right now reading the article carefully.

I encourage you to post more pictures of your single crystals here at the FMF for all of us to enjoy them. I'm sure all the readers will appreciate it a lot.

Thank you!

[Jordi Fabre]

We got the kind permision of the Mineralogical Record to publish the John's article here. It would be already published, but today we had problems with one of our computers, so I will do it at Tuesday.

Jordi

[Duncan Miller]

Hello John

Your photograph of the "screw dislocation" in beryl has had me puzzling over a similar crystal that I bought years ago from a deceased estate (so I don't know its provenance, possibly the same as yours?). I shall post a composite photograph of it immersed in oil, from two different points of view. This crystal is 55 mm long and has several of these helical inclusions, some running from end to end. Where they crop out at the ends, the cores don't appear to be hollow, but they could be microscopic tubes. There are plenty of very fine straight ones in this specimen. I have two questions.

First, are these really dislocations? I thought dislocations were microscopic lattice defects requiring transmission electron microscopy to image them. Please correct me if I am wrong.

Second, if they are not dislocations what are they? They certainly do look screw-shaped, but the screw blades do not run all the way around, and under magnification they look more like slightly twisted planar outgrowths or possibly even cracks. Some cores have blades/cracks emanating both right and left. Their spacing is amazingly regular, which means there must be some crystallographic control; but it cannot be cleavage, which in beryl is imperfect and parallel to the basal pinacoid {0001}. These blade-like features are oblique to the basal plane. Could I ask you please to look closely at your specimen to see if you concur?

I don't have an answer to the question of their identity, but if I ever get around to faceting this specimen (two faces were ground already when I got it) I will try to analyse an exposed core to see if there is a second mineral present.

Duncan Miller

[John S. White]

Xenolithos:

There is no doubt in my mind that your crystal came from the same pegmatite as mine. The inclusions appear identical. I agree that the "screw" does not resemble what we tend to think of when referring to a screw dislocation, but I cannot imagine any other mechanism that could produce helical designs in the crystal, particularly ones that are paralell to the "c" axis, as these are. The good news is that John Rakovan at Miami University in Ohio is initiating a study of this phenomenon and I will invite him to respond to your comments. Attached is a close-up photo of my beryl, photo by John Koivula, who calls it a growth spiral.
(for further discussion follow this link https://www.mineral-forum.com/message-board/viewtopic.php?p=13653&highlight=#13653).

Carles Millan, I love your taste in specimens, each is elegant in its own way, and the photos are outstanding. Thanks for sharing them with us. I will post some single crystal photos that were not used in the article.

[Duncan Miller]

Thanks for your quick response John.

I look forward to what John Rakovan might have to say about these helical inclusions. John Koivula's beautiful photograph shows very clearly the slightly twisted "blades" sticking out like paddles. Very weird and intriguing.

Duncan Miller

[John S. White]

Here is a single crystal I just acquired at a local show two weeks ago. It is an epidote from the Han Dan mine, Hebei Province, China, and it measures 4 cm across. It will find a good home in my single crystal collection. Note that it closely resembles epidotes from Prince of Wales Island, Alaska, but it is not twinned as they tend to be.

[Jordi Fabre]

To see the article about the John White collection in the Mineralogical Record, please use this link: https://www.mineral-forum.com/message-board/viewtopic.php?p=5606#5606

Jordi

[John S. White]

Another favorite, this time a perimorph of quartz after calcite from the Djurkovo mine, Laki district, Rhodope Mtns, Bulgaria. You can see from the back view that the quartz cast is completely hollow, the calcite is gone. The piece is about 8.5 cm across. I apologize for the poor photos, they are mine.

[garchin]

Hi John,

I like your quartz collection very much. It is less pretentious and still one of its kind.
Like your last picture I cannot help imagining an animal surviving on a calcium bicarbonate diet:P Regards, Gar.

[Gail]

I am still drooling over the artichoke quartz!

[John S. White]

Here's one I acquired this past Tucson Show. An iron-stained quartz with hematite from Lechang, Guangdon, China, 8 cm high.

[John S. White]

A fun piece to show people. It looks like a mouth with teeth and I bought it from Peter Megaw about five years ago. It is, of course, chalcedony, and the teeth are quartz crystals. The locality is Chihuahua, Mexico, a big state but that was all the information Peter was providing then. It is completely round, about the size of a ping pong ball.

[Gail]

So, now I am drooling over these two...

[John S. White]

No Carles, I am not an insomniac, I just like to do my email, etc. from 5:00 to 6:30 in the AM, before my wife gets up, have to walk the dog, etc. I make up for this extreme behaviour by having a nice nap in the afternoon, assuming the phone does not ring.

Here is one of my single crystals that did not make the article in Min. Rec. It is a fluorapophyllite from Maharashtra, India, 3 cm in length. The photo is by Isaias Casanova.