Minerals, Rocks, and Geology Thread

[MineralMan]

For about 10 years, I was in the business of selling mineral specimens to mineral collectors from a website. I closed that business in 2005, however, I maintain an interest in the subject. I suspect there are DUers who are also interested in the subject, so I've started this thread. If you're interested in rocks, minerals, or geology, let's hear from you. If you have questions about the subject, I'll be glad to try to answer them. I have a lot of resources, and had to put myself through the equivalent of a graduate degree in mineralogy to make the business go.

Here are some photos of some of the display cases I had in my shop, which also served as a mini museum for the local schools and casual visitors:





If you're a collector, let's see some photos of what you have. If you found an interesting rock, post a photo, tell us where you found it, and I'll try to identify it for you.

[MineralMan]

1. Watch out for the third shelf from the bottom in the second photo.

It holds a bunch of radioactive minerals. Fearful people should "stand well back," as they say in England.

[lazarus]

2. two things

I absolutely love geodes. What's the most cost-effective way of acquiring these in varying sizes?

Two: Is it true that lapis is all over Afghanistan? That's what Richard Engel said on Rachel's show the other night. I love lapis, too.

And where do you put the emphasis in the second part, lazuli. Is it LAZuli, LAZuLI, or laZULi?

[MineralMan]

3. Probably your best bet is to haunt ebay for them.

You have a good chance of finding nice bargains there. Beyond that, search the web for geodes at rock shops and mineral dealers. Prices are down a lot right now, so there are bargains everywhere.

Lapis Lazuli isn't exactly all over Afghanistan, but it's the traditional source for that rock. It has been the primary source since the earliest days of civilization, and still is. Emphasis is on the first syllable of Lazuli.

It's a rock, not a mineral, because it's composed of more than one mineral. It's a metamorphic rock, made up of lazurite, sodalite, and pyrite. The last forms the golden flecks that make it so striking. Other minerals sometimes occur in it, too. It's found in marble deposits.

It's long been used as a semiprecious stone and a building material. Beautiful stuff.

Edit to add: Lapis is also found in other parts of the world, but not in the size and quantity found in Afghanistan. Ebay's a good source for this, too.

[conscious evolution]

4. woo woo new age shops

are also an excellant place to find interesting rocks.
Crystal Blue in Atlantas L5P area has hundreds of differant specimens from all over the world.

[MineralMan]

8. That's true, but you do have to watch their prices. There's a tendency

for them to overprice, compared to other outlets. Still, there are few retail mineral dealers any more.

[lazarus]

7. thanks, MM!

I was leery of the woo shops, figuring they'd hike the price up because the crystals were aligned with ley lines or some such nonsense.

[conscious evolution]

11. The crystals at CBlue

do seem to be a bit on the pricey side to me.
They have one giant crystal priced at over $800.00
Same with some of their semi-precious stones.
However,most of their rocks seem,to me anyways, to be fairly cheap.They have a lot of interrestingly colored rocks that are in the $1.00 to $10.00 range,depending on size.Of course,someone with more knowledge will probably think they are overpriced.They do sell a lot of them,though.When it comes to pretty rocks one will never find around here I guess people are willing to pony up for them.

[MineralMan]

12. It's a complicated marketplace. I've seen specimens you might not

even glance twice at sell for mid 5 figures.

These days, just about anything you might want is on ebay. The market shifted to that outlet around the time I closed my website. It became impossible to compete with the sellers there, and even harder to find good specimens in large enough quantities to keep the website alive, despite attending three major mineral dealer shows a year.

Ebay is the place to find what you want, no matter what it is. It's a constantly-changing mineral show there every day. Just go browse a bit. Great photos, great specimens, great prices. Just be sure to pay attention to the feedback and ratings and you'll do just fine.

[AlecBGreen]

5. I love Geology!

I teach it @ the high school level. I actually backed into the job (I was a bio major) but now Im hooked!

I live in the Shenandoah Valley, with the Blue Ridge to the east (just out my kitchen window) and the Massanuttan (and the rest of the Appalachians) to the west. This is a GREAT spot for geophiles!

I went hiking with my wife and found some Mississipian fossils the other day. ill try to get a good pic uploaded. Thanks for the thread!

[MineralMan]

10. That's a great area, with some wonderful mineral resources.

Keep your eyes down as you hike around, and carry a loupe with you to examine specimens. Casual collecting generally produces specimens with tiny, but perfect crystals of various minerals. A close look can often reveal beautiful surprises.

[Igel]

6. Here's a question.

I grew up in an area with utterly uninteresting rocks. Lots of dirt, not so many rocks unless they were used in landscaping. Still, I collected because in 3rd grade our "rock collection" was an assignment.

At some point, I got a "rock" from a friend. He was given the thing by his uncle, a lump maybe 2" x 3" x 4" (give or take an inch--this was 40 years ago). The teacher couldn't identify it. The books we looked in didn't identify it. I suspect when I moved it was eventually tossed by my parents, so I don't have a sample to photograph; it constantly shrank in size, so if I had kept it it would have vanished by now, anyway. But it's bugged me for 40 years: What the hell was it?

Now, it might not have been natural. It might have been the result of some steel-manufacturing process, something chipped out of a blast furnace or formed as a lake of slag cooled or some build-up on the open hearth furnace. He didn't know, his uncle wasn't available for comment.

Here's my description:

It was fairly heavy. Not as heavy as a similar volume of tin or lead or even steel, but heavier than the silicate-based rock that we mostly had access to. At one point I had it's density in g/cc, but that's long forgotten.

The lump was homogeneous, but not really a good solid. It flaked constantly, little silver flakes rubbing off. If it broke, it was stratified--it clearly wanted to break mostly parallel to one plane and any break along any other direction yielded a jagged surface. But it can't be said to cleave because it was *entirely* little silver flakes, consistent and pretty uniform in size to the naked eye--each no bigger than a millimeter in any direction. If you did "cleave" it along a single plane, you'd see that this usually failed and you'd get little step patterns form where some flakes stuck to some neighbors more than others. Of course, the steps were very, very short.

I don't recall that the flakes had an obvious shape, square or octagonal or anything. Once they rubbed off, they tended to like having their flat surface stick to things.

The lump was silvery grey when looked at perpendicular to the flakes' plane; it was a dark, dull gray on edge. This might be an emergent property in that each flake was actually transparent; I don't know. It looked precisely the same when under water and under solvents like cyclohexane. Each flake looked silvery grey. They were too small to try to cleave, so I'm of no help there. Conceivably it might have been mica, ground up and compressed, but most of the mica I've seen is yellowish-brown.

I've cleaned up most of the "mysteries" from my childhood. This one is left unsolved.

[MineralMan]

9. Hard to say, really, what that was. A lot would depend on where it

was found. Hematite is grey and occurs in roughly hexagonal thin plates. Very soft, and generally a bit greasy in feel in bulk specimens.

However, the transparency sort of eliminates that. That's pretty much a sign that what you had was one of the micas, which can also be grey and can also form hexagonal plate-shaped crystals. That would be my guess. If you can pin down the location where it was found, I could probably be more certain.

[HiFructosePronSyrup]

13. Bismuth, how does it work?

[Geostudent]

14. Two things to note..

The color is simply oxidization causing the colors to change. Same basic idea as an oil sheen in a puddle. The growth pattern is something called a hopper crystal. Information on their growth can be found http://en.wikipedia.org/wiki/Hopper_crystal">here.

[MineralMan]

15. Those colorful bismuth crystal clusters are man-made, and are not

natural minerals. Native bismuth is vanishingly rare in nature.

They're very attractive, though, so they're pretty popular, especially with people who don't really collect minerals. That iridescence is fascinating.

[Odin2005]

16. That is so cool!

One of my favorite rock types is gabbaro, which is like basalt but has much bigger cystals. There are huge formations of it in the Duluth area, the preserved evidence of a billion-year-old rift valley that "failed". It's a very pretty rock.

[MineralMan]

17. Rocks and minerals are great! Thanks!

[chemenger]

18. I also greatly enjoy geology and collecting minerals

Started off at Penn State as a geology major then switched to chemical engineering. I had a small but nice collection of thumbnails years ago but lost it. Since then I have been trying to rebuild it little by little. Problem is that several sources of thumbnail specimens have dried up.

There used to be a gem and mineral shop outside of Youngstown, OH called Adamas that had drawers full of thumbnail specimens for sale. As far as I know it is out of business. David Shannon, a well-known, Arizona-based mineral collector and mail-order dealer (yes, this was before PCs) of reasonably-priced specimens passed away several years ago. (interestingly, David Shannon was a chemical engineer) I understand his wife and sons are continuing his business but I haven't spent much time on there website. There was another mail-order dealer (David G ... I can't remember his last name but I think it may be Goode) but he offered nice thumbnails at reasonable prices.

There used to be gem and mineral shows locally at several of the area malls once or twice a year that sold nice mineral specimens but I haven't any of those locally for a number of years.

It seems that there are more people into mineral collecting which has driven prices for even thumbnail specimens higher than I can reasonably afford.

I have bought a few specimens via EBAY with mixed results but I prefer to select and purchase only after I have examined them. Also, I noticed that many specimens are sold either w/o (or with inadequate) locality information. IMO, the locality information is every bit as important as the mineral name.

While surfing the internet one evening, I came across a California-based dealer that sold trimmed specimens of just about every type of igneous, sedimentary and metamorphic rock under the sun> meant to bookmark it but forgot. Was never able to relocate it.

The same publisher that publishes Astronomy magazine (Carstens) used to publish a magazine devoted to the earth sciences (geology, paleontology, meteorology, oceanography) but it was short-lived.

I, for one would support a Minerals, Rocks, and Geology Thread.

Oh, and BTW, great collection!!!!!

[Nihil]

19. Thanks for the thread MM.

Nice collection too! :hi:

I've always had a love of rocks, both for the visual/tactile aspects
and for the science behind them. You can learn so much just from looking
at the things: no longer "just a rock" but a little package of information
that can tell you all sorts of things - the environment where it was
formed, the chemistry, the physics (heat/pressure/duration), maybe even
the lifeforms that were around at the time as well as a record of the
changes that it has undergone since.

As for the larger scale structures ... there so many things to learn from
"rocks" if you are prepared to look - and that's apart from their beauty!

:toast:

[lazarus]

20. just went to the rocks and gems exhibit

at the San Diego Natural History Museum. Very nicely done. Haele and I agree that the raw rocks and gems are prettier than the jewelry, usually.

I saw a slab of lapis that was just gorgeous. Not enough peridot. And I fell in love with this huge slab of something called pyrolusite that looked like the ashes left over from a camp fire, only pure black.

Lots of tourmaline all over the exhibit. And a nice display of benitoite, which is only found here in California.

They had some crystalline gold formations, and a piece of jade as big as I am, if not bigger.