Marialite vs Meionite

Hi all, I recently posted a Scapolite crystal and had it posted as Scapolite. It has been changed to Meionite?? How can one tell the difference between the two. I know the Sodic end member is Marialite and the Calcic end member is Meionite. What test can I do to to tell which is which?? I would guess the Calcic member has more Calcite yes?? Is an acid test in order??

Thanks Andrew J.

Which photo was it? Usually we "complain" and then change it, if there is no response after a while. Sometimes a locality produces only one of the invisible species from a group. In that case one can be very certain of the species, but otherwise it is wrong to invent a species name.

Hello Andrew,

I don't think that there are any simple tests that you can use to differentiate the two end members.

I enquired of the Canadian Museum of Nature uears ago and I'm pretty sure that they had found only meionite when scapolite group samples from various localities in the Grenville were analysed. I'm going to ask again to make sure and then I'll let you know.

Hi Rob, this is the photo I posted.

I posted it as Scapolite which it is. What type I don't know? It was found in the dumps last year at Cardiff Uranium mine. It was originally attached to a Calcite/Fluorite matrix which I removed it from.
David, thanks for the info. If that is the case about Scapolites from the Grenville area then I'm OK with that. That means I learned something new today. I have a similar bluish grey piece in my photos and that wasn't messed with? Where's the consistency? There are Mindater's that know a lot more than I but an explanation on how they know and why is the answer I'm looking for? I'm eager to learn so don't anyone take this the wrong way. I'm just a bit confused is all.

A.J.

The locality already claimed it was a meionite locality so offering a generic name seems to suggest you do not believe you have the species listed. Marialite is a relatively rare member of the scapolite group. If you are labeling it "scapolite" because you believe it could be a member of the group which has yet to be reported from the location, then it should be changed back and your suspicions would be valuable to comment on in the specimen description. Group names are valid to use at mindat.

Best Wishes, Van King

Hi Andrew,

I checked with Michel Picard at the Canadian Museum of Nature. Turns out that I was wrong in my recollection. Of the Scapolite group minerals from the Grenville that they have analysed, 55 are meionite and 21 are marialite with some locations having both!! So back to the drawing board.

Van, I totally understand what you are saying. But why then are there other specimens photos in the Cardiff locality page down as Scapolite then? That's what is confusing me. If Meionite is listed I beleive it could be such a piece. Thanks Van for informing me of Meionite being at Cardiff. It was an oversight by me when looking at the Loacality page.

Andrew..

Can we change it back to scapolite, please?

Jolyon

Can you measure a refractive index? Although a plot of the refractive index for changing Na/Ca content is a curve, it is pretty close to a straight line. As long as the result is not too close to 50/50, comparing the N to those of the end members might give you an indication. (I think I am correct on this and would enjoy hearing from others)

Dave, could you please ask Michel if Marialite has ever been observed at the Cardiff. Somewhere I have an old ROM catalogue of Ontario (or Canadian?) occurences, but I can't lay my hands on it.

Donald could well be right. The Afghan purple scapolites are quite gemmy and susceptible to this. Does anyone know where they sit in the series?



Edited 1 time(s). Last edit at 09/23/2009 04:52PM by Rob Woodside.

Andrew

Unfortunately, this isn't going to help. When the Cardiff Mine was in operation the mine took ore from other prospects in the area for processing. As a result, the material on the dumps is not necessarily from the Cardiff Mine, but from the local area. This was told to me by a couple of local collectors about 30 years ago. Seems to have been forgotten. So without analysis, your scapolite could be either end-member.

John Duck

If he found the sample on the waste pile it is not likely from some other property. Furthermore there was never a mill on the Cardiff site so why would they bring ore from some other property there? Bicroft Uranium Mines had a 1000tpd on their property in the same township, maybe the locals were talking about that.

Thanks everyone, I will wait and see if Dave can come up with a conclusion?? Also I can second what Reiner said about the mill. There are no mill ruins at or near the site. Just the capped off shaft where the Headframe stood and a sealed up Adits. John, the piece came from a Calcite / Fluorite mass that is predominant at Cardiff. Thats the matrix host for Uraninites which Cardiff is famous for.

I will ask!

Rob, if you're talking about the 1977 Slatterly catalogue of Ontario specimens in the ROM, there is one specimen of scapolite from the Cardiff Mine listed only as "Scapolite Group". In fact, there are no separate listings for marialite or meionite in that document.

Van King is listed as the reference for meionite at this location. Perhaps he could chime in.

I'm working with Michel tomorrow so I'll ask him about any scapolite he's got from this location, but that will only help us confirm the presence one or both species from this location, it doesn't help us with Andrew's piece. The possibility of having both marialite and meionite in one location means unless it's analyzed, or somebody's done a comprehensive study of the scapolite group minerals at this location, we can only call it scapolite.

All,

According to Michel Picard at the Canadian Museum of Nature, there is no scapolite specimen from the Cardiff Mine at the CMN.

Andrew,

Yes the calcite/fluorite matrix with the uraninite cubes occurs at the Cardiff mine and is in evidence (at least it was) in the ridge outcrop north of the mine that has been previously described on Mindat.

Everyone. Regarding local material being brought to the mine property; I am only relating what I had been told and yes I know that there was no mill at the site. If someone has experience with the mine operations and therefore knows that no outside material was brought to the site then I defer to that individual.

Thanks for checking into that Dave. Much appreciated. I guess I'll just call it Scapolite. Thankyou!

A.J.

Ref.: Sabina 1986
Just south of Pusey lake is the Wilberforce graphite mine where there was a mill and material was processed from the National Graphite mine in Monteagle township. This could be what the some people may have been referring to.

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A buena hambre no hay pan duro

1) Dave - did that scapolite study get published? I'd LOVE to get a copy to help with Ontario scapolites and ontariominerals.com

2) No offense, but I'm not sure photos like that contribute much of anything. The mineral is common in crystals, do we need dubious photos of lumps? I don't know what the site policy is on quality of photos, personally I'd like to see some higher standards. Again, I intend no offense, I was a beginner collector once and to be honest most of my photos suck, though I think I'm improving, and I'm begining to suspect that DSLR's are in fact much like women, in that I find neat new buttons that do amazing things, every day!

T