FMF - Friends of Minerals Forum, discussion and message board

[David]

Hello all,
I have a big question.
Which is the maximum number of clearly visible minerals on a collectible specimen you know of?
Thanks

[Tobi]

In my personal collection the maximum number is 4, i have specimens with

- azurite, fluorite, baryte, malachite (Aouli, Morocco)
- quartz, hematite (but not really visible, only colouring the quartz), siderite, fluorite (Erzgebirge, Saxony)
- calcite, dolomite, galena, chalcopyrite (Sweetwater Mine, Missouri)

But i've seen specimens with 5 or 6 different minerals and i suppose it can be even more, maybe nearly 10 ...

[mmauthner]

Hi David,
You might want to define "clearly visible" a bit more. Are you including specimens with micro sized crystals? That is, specimens with crystals best enjoyed under a microscope, whether a micro"mount" sensu stricto or not. Even "visible to the naked eye" can be subjected to all kinds of hair splitting. Whose eye and at what distance?

If you are concerned about paragenesis or mineral relationships, why limit to "clearly visible"? Microscopic inclusions can sometimes tell important stories.

Cheers,
Mark

[Pierre Joubert]

The best I can do is a specimen containing Quartz, calcite, epidote, analcime, phrenite and basalt.

[Tobi]

I would not count basalt as a mineral since it is a rock ...
... well, but the more it could count as several minerals ;-)

[Jordi Fabre]

Panasqueira is worldwide famous by its richness in different species on the same sample. The specimens mined there frequently has at least 4-5 different species and sometimes it could arrive to ten (or over)

I add an example from there, with 10 different species.

[Peter Megaw]

As Mark and Tobias note, a lot depends on how small you go and if you count rock forming matrix minerals. Specimen size matters too as there's more room for more species on a single piece. Complexity of geologic environment is also a major factor as Jordi points out from Panasquiera. Other polymetallic systems, like Santa Eulalia and Naica are also characterized by multiple well crystallized macroscopic species:

Here's a small (toenail) specimen from Naica with

bournonite, galena, sphalerite, pyrite, arsenopyrite, chalcopyrite, quartz, and calcite all growing on a fluorite crystal (does not show in picture)

[prcantos]

I think this is not a technical question of course, but only for pleasure! I would say that it depends on the size of the specimen. Thus there is an unique and maximum solution: the whole Earth considered as "collectible specimen"!!!

Greetings!

[alfredo]

Alkaline igneous rocks are famous for including a wide variety of species in a single sample. Finding 8 species in a 'toenail" or "miniature" of the ankerite carbonatite from Bolivia is really easy! I suppose Mont Saint Hilaire collectors must have samples with more species in them.

[Tobi]

[David]

Thank you all,
The most mineral rich specimens in my collection contain 4 maybe 5 minerals. Most specimens contain one or two minerals. This is an interesting topic from my point of view since mineral diversity can dramatically increase the beauty of one specimen, especially if those minerals are in contrasting colors or different shapes.
I mentioned clearly visible because a sample may contain minerals in trace amounts which is not really relevant from my point of view. I suppose clearly visible should include micro mounts now that you’ve asked.
I mentioned collectible specimen to make it clear I don’t refer to a ten ton rock which might indeed contain a considerable number of different minerals but again that wouldn’t be relevant for a collector like me. You don’t have to interpret every single word; I just wanted to know what you can tell from your experience. Taking into account all of your answers my conclusion is that collectible specimens containing more than 5 minerals are rather rare, but specimens from certain locations might contain up to ten. Therefore I should keep that in mind when I compare specimens. Thank you, your answers were very useful.

[Carles Millan]

[Tobi]

[prcantos]

Obviously I was only joking before ;-) Now I am serious. If you are looking for many different species together, you should consider these types of rocks and places:

- Pegmatites and rocks in dikes, sills, veins... Here pneumatolitic and hydrothermal processes usually generate idiomorfic crystals of many different minerals.

- Foid syenites: quzart, feldspars, mica, pyroxen, amphibole, foids, zeolites, calcite, apatite, zircon, titanite, eudialyte, eucolite, rinkite, aenigmatite, pectolite, lorenzenite, opaques... (from Maresch/Medenbach, Rocks, Munich 1987; spanish ed. Barcelona 1990). Of cours it's not supposed to have all together and visible!

- Cavities in volcanic rocks: geodes, druses, miaroles...

- Carbonatites (as was said before) usually bear odd mineral species, sometimes with good crystals.

- Metasomatic rocks (such skarns).

- Oxidation zones often show good and colourfull different crystals as well.

I wish it would help you.

[Pierre Joubert]

Unfortunately not all minerals can be seen: Quartz; epidote; calcite; phrenite and analcime. What about hematite and other inclusions, do they count?