FMF - Friends of Minerals Forum, discussion and message board

[Tom Mazanec]

I suppose quartz is most common.
What is the rarest mineral of all?
What is the rarest of your collection?

[Bob Carnein]

I can't say, but I don't think quartz is the most common. If you just look at Earth's crust (including the oceanic part), that's probably the plagioclase feldspars. Even continental rocks are likely to have more potassium feldspar than quartz.

[Tobi]

[Bob Harman]

If Tom's only question was "What is the rarest mineral in your collection" it would have been an interesting question.
However one part of his question was worded as "What is the rarest mineral?" and that part, in my opinion, is an unanswerable question. Virtually all very rare minerals and as yet undiscovered minerals theoretically might be the rarest of all, but any of these has unknowable amounts in collections, museums and still in the ground.

As to the rarest in my collection.....I do not know because the vast number of my specimens have never been analyzed so I don't know what I don't know! CHEERS.....BOB

[Jamison Brizendine]

The other problem in asking with rarity in ones collection becomes how does one define "rarity"? I know of an Ohio jeweler who has cut many gems, including a Rolling Rock beer bottle. I would say a faceted gem out of a beer bottle is a pretty rare thing, but finding a broken beer bottle is not.

Some common minerals, like quartz and fluorite, are very rare in certain localities, but very common in others. What about a mineral's crystallography or unusual habits? Has the mineral been subjected to deformation (faulted or folded?). What about lack of damage or size? "Rarity" becomes more of a subject of personal preference. Sometimes people perceive objects as rare, but are actually very common to see for sale.

I have minerals in my collection, like my calcite from Newport, Tennessee, that would seem rare, only because I'm the only person who would be stupid enough to collect such a specimen that would seem "low-grade" to others.

[Debbie Woolf]

Orlymanite from Wessels, KMF, is probably the rarest in my collection.

[alfredo]

Jahnsite-CaFeFe.... Only one walnut-size nodule was ever found, with a few microcrystals in the central cavity. It was broken into 6 specimens, and I was lucky enough to get one of them. But there are also plenty of species that exist only as a single sample - and I don't have any of them ;((

[Jordi Fabre]

One of the most rarest and at same time nice mineral existing is this Andyrobertsite with Calcioandyrobertsite from Bill Pinch collection. It seems that just very few, less than 5 specimens, were found (for the moment ;-)

BTW, I strongly recommend this thread: The Bill Pinch collection

[Bob Harman]

Adding further thoughts to my reply from above. Tom's question might be answered by what Jamison discussed.....what might be the rarest mineral in Ohio?

Or I might answer: What is the rarest mineral that I know of in my collection of Indiana Geodes?
I have the only pictured example of fluorite in an Indiana geode; otherwise this mineral is listed only as "reported to occur" when lists of secondary minerals in Indiana geodes is reviewed. In addition, I have pictured small malachite and chalcopyrite crystals in Indiana geodes. These copper minerals are also very rare with malachite also just "reported to occur" in Indiana geode secondary mineral lists.
These pictured examples of common minerals, but rare in certain circumstances can be seen in the Midwest Sedimentary Geode thread on the Mindat website CHEERS......BOB

[lluis]

Hi, Jordi

Nevertheless, I have a piece that was sold to me as calcyoandiroberstite. Not as nice as the one you placed in the Forum, but a tiny spec in tetrahedrite.... I have found several on the net, more than 5...
Question is if they are what is said....
I think mine is so, but to think is not to know. Sold by a honourable seller, so, I suppose it is.....

Painites were one time very rare. Now seems that they are not....

I think that there are many rare minerals, probably the most is the one Alberto mentioned. Wish to have one!

With best wishes

Lluís

[Tobi]

As a collector of "common stuff", I must confess that I've never heard of some things you guys are talking about. Andyrobertsite, Calcioandyrobertsite, orlymanite ... after 25 years of collecting minerals I feel like a greenhorn when I read that ;-)

[newryqs]

There are many minerals known in a single grain. Some minerals are known only from a polished section, before the IMA required a x-ray data set. Some minerals such as acanthite are not present in anyone's collection, that I know of, but that is because it is unstable at Earth surface conditions. There are possibly some species that are extinct. Downeyite may be in that category, depending on whether the container holding it leaked. Selenolite is also nearly extinct for the same reason. Many minerals are much more common than believed due to lack of analyses for individual specimens. There are some minerals that are so rare, they aren't even on the specimen.

[lluis]

Hi, newryqs

"There are some minerals that are so rare, they aren't even on the specimen."

Very good phrase, my friend.
It reminded me of the case, a long time ago, about a collection of platinoids, worth much money, that when analyzed, I think to remember that approx 90% of the samples were nothing, and of the remaining 10%, the majority were badly analyzed..... A sad case, I think.... But maybe not so uncommon...

I have a pyrope, analyzed, that came with two labels: first as ruby, then relabeled by a prominent collector as zircon...to be shown as pyrope (garnet)..... Not rare none of them. Just not well-labeled.....and not in specimen!

With best wishes

Lluís

[Les Presmyk]

I will put three specimens into the conversation. I have the co-type specimen for laurelite, aravaipaite, grandreefite and pseudograndreefite from the Grand Reef mine in Arizona. It is a palm sized specimen. I have just acquired a Bobmeyerite from the Mammoth-St. Anthony mine, Tiger, Arizona. The first is a displayable specimen and the second, while with numerous vugs containing the bobmeyerite, it requires magnification to see the mineral.

My third specimen is not a rare species but I am going to state it is probably the only remaining piece of sphalerite from the Mammoth-St. Anthony mine, Tiger, Arizona. It is not even crystallized. I mention this piece because it is an example of rarity based on locality, not on the actual species. Who knows, maybe someone has a crystallized sphalerite from Tiger they will let me know about.