FMF - Friends of Minerals Forum, discussion and message board

[John S. White]

Here is another topic for the Forum, triggered by the new set of photos from Tracy of "stalactites" from her collection:

https://www.fabreminerals.com/forum/Message-Board/viewtopic.php?p=1307#1307

I have a bit of a problem with calling these elongated crystal groupings stalactites, which I do not believe most, if not all, of these are. The term stalactite has a rather specific meaning, and it goes something like this: "Icicle-like growths of a carbonate mineral (usually) formed by water dripping from the ceiling of a cave or cavern." Most are usually calcite but the rhodochrosites from Argentina are a notable exception. The term stalactite is specific in that it refers to those formations that hang down, as opposed to stalagmites which grow up from the floor from the same drippings. In the case of Tracy's specimens, they could just as well be stalagmites as stalactites, but I do not believe they are either. I realize that Marty Zinn used to call all such elongated growths "stalactites" but I am sure that was just a term of convenience so that he didn't have to describe every time what it was that he was then specializing in. Note that the vast majority of true stalactites are not covered by visibly distinct crystals.

Perhaps we can come up with a new term for such formations, in which case I feel we would be doing the hobby a favor.

[Tracy]

Hi John -

You raise a really interesting question, and one which I was actually musing over last night while posting my photos. It went through my head that maybe these weren't stalactites at all, because I couldn't imagine the pyro crystals forming out of dripping solutions, and the quartzes visually suggested upward growth rather than downward. Of the 3, the one which looks most like a stalactite to me is the pyrite, however it doesn't meet your definition of a stalactite. Nevertheless I went by the label and information communicated to me.

I will revisit the "stalactites" in my collection and question almost all of them I'm sure. In the meantime, I propose changing my theme of last evening from "stalactites" to "elongated crystal formations which are not contacted except at one end." Would love to hear more comments on your proposal to find a new name for these things - would be worthy of a new topic in my opinion.

Thanks for clarifying -
Tracy

[alfredo]

Opal "stalactite" (actually, I think, a stalagmite) from cave in hornfels, Huanuni, Bolivia. Formed by sulphuric acid acting on silicates, rather than the more usual carbonic acid on carbonates.

This specimen went from me to Marty Zinn to Rob Lavinski to... ?

[Pete Modreski]

The "stalactiites" pictures and discussion have been interesting (I've been busy, just catching up on viewing them all now).

One can sometimes perhaps get away with calling some of these mineral formations "stalactitic", which can imply stalactite-like shape without necessarily really have grown quite that way. "Stalactoid" would be even better, but I've never heard anyone say that. Or one can just keep saying "stalactite-like" and leave it at that.

Malachite, of course, is another mineral that commonly forms very stalactite-like (or, stalagmite-like) growth.

Alfredo, your opal "stalactite" is reallly something. Are you sure it isn't a petrified one of those new compact fluorescent lights? You might try plugging it in and see what happens.

And Tracy, off this topic, but that was a particularly nice dioptase cluster... reminded me of one of those artificial clusters from a crystal-growing kit! : )

Pete

[Tracy]

Off this topic, thanks Pete! It has a wonderful NATURAL glow.

Just for fun: hastily taken (indoor/outdoor) photos of a calcite helectite from Bisbee, 10 x 8 x 6 cm, with points of attachment at both ends. Would love to know how these formed - am guessing it's in a manner similar to stalactites and stalagmites, but I can see distinct crystals throughout. Would helectites qualify as stalactite-like formations?

[Les Presmyk]

Stalactoids, I love it. Tracy, someday when you are out in Arizona you will have to come by and see our collection. We have a number of Arizona stalactoids you might like to see, especially the crystallized helictites that have been collected out of some of the mines in Bisbee.

[Pete Modreski]

I should wait and let others comment on your question, Tracy, and of course likely they will (John?), but I'll shoot out a reply too.

Probably depends on how closely one requires "stalactite-like" to be truly "stalactite-like". In fact, a helictite (the correct spelling) is itself not quite a stalactite, just related, one might call it "stalactite-like"; they are both "speleothems", the general name for all cave formations. Well, thinking about it, perhaps helictites are considered to be a type of stalactite.

Helictites are generally defined as mineral growth formations in caves that are not controlled by gravity, but grow in irregular directions, determined by the orientation of crystals at the tip of the formation. Usually in caves, they are of aragonite, and they are fed by water moving through a small central channel within the helictite. I'd never really thought about whether those irregular Bisbee calcite growths would be considered helictites or not; is that what people commonly call them?

I've always loved those Bisbee calcite formations such as you showed, especially the curved, scaly-looking ones that look for all the world like shrimp (minus the legs and all, ready to be eaten as shrimp cocktail).

Pete

[Tracy]

...from the root word helix, I assume - makes a lot of sense. Thanks for the spell check!
Here's another one I have, 8 x 6 x 3.5 cm. The crystals aren't as large, but the form is fun - nicknamed "the dog."

Les, would love to see your stalactoids. No plans to come to AZ any time soon, but if things change I'll let you know. Thanks! :-)

[John S. White]

There you go Alfredo, muddying the waters!

Pete
I see nothing wrong with stalactite-like or stalactitic as long as it is used in a discriptive sense and not a generic one. But stalactoids just doesn't roll off the tongue, and shouldn't it be stalactitoids, which is even worse?

[Pete Modreski]

"The Dog" is just incredible! Surely it's glued together and constructed, Tracy. Needs to be labeled "not only repaired, but creatively enhanced"!
(just kidding, just kidding)
Pete

[Tracy]

John, one could argue that "stalactite" doesn't roll off the tongue any better than "stalactoid" does...

[Les Presmyk]

Tracy, thank you. I am still trying to figure out where John came up with "stalactitoid" since we did not start with "stalactitite".

[Pete Modreski]

This is gettin' pretty complicated. Maybe if the original word had been stalactitite, the "oid" version would become stalactitititoid.

But what this reminds me of, is one year way way back, over the P.A. system at the Tucson Show, announcing one of our meetings, the announcer broadcast the meeting or lecture of the (enunciating the 6 syllables quite clearly) "FRIENDS OF MINERALOLOGY". Anybody else remember that? (quite likely, it still happens)
Pete

[Tracy]

Thanks all for brightening my afternoon!

- Seriously though, what's a recommended way to label my stalactites-that-aren't-really-stalactites?" Personally I think "stalactoid" could be a useful term, if I (and/or other hobbyists) don't know for certain whether it is stalactite or stalagmite or just an elongated growth formation (and might even encompass helictites)...

Hmm, but then thinking a bit further, would dendritic specimens qualify as "stalactoid?"

[Les Presmyk]

Dendrites are a completely different animal. Besides, I don't see your pyromorphite or pyrite as stalactites anyway. Why call them anything other than the mineral they are?