Discussions

💬 Home 🔎 Search 📅 Latest

╳Discussions

💬 Home 🔎 Search 📅 Latest

Groups

Recent Images in Discussions

Improving Mindat.orgicky lattrapite photo

27th Feb 2013 16:25 UTCTony Peterson Expert

The type photo for lattrapite is a blown-up, pixelated, low-res, indifferent image of a crappy, busted specimen. There are numerous better ones available.

Tony

27th Feb 2013 16:42 UTCLászló Horváth Manager

I agree. Furthermore, lattrappite from the St. Lawrence mine is doubtful and to my knowledge has not been confirmed in the literature, whereas perovskite (visually indistinguishable from latrappite) is quite common there. My guess is that many latrappites in collections are actually perovskites.

27th Feb 2013 20:37 UTCDavid K. Joyce Expert

All "latrappites" from that locality, that I have had tested have turned out to be, at best, niobium-rich perovskite. Where is the type specimen? Perhaps it should be re-examined?

David K. Joyce

27th Feb 2013 20:43 UTCReiner Mielke Expert

What about this one? http://www.mindat.org/photo-1340.html

28th Feb 2013 04:34 UTCDonald Doell Expert

Latrappite and Perovskite occur at Oka.

Microprobe analysis is needed on all samples. Although theoretically you could distinguish these with x-ray diffraction, for example; as Nb increases over Ti you get a larger unit cell. You can't tell based on appearance.

Clear Nb dominance over Ti is well documented at Oka. The original 1963 Nickel article had Nb 43.90%, Ti 10.05%, but this was bulk analysis and may have been contaminated by pyrochlore.

Fortunately we have "Latrappite: A Reinsvestigation" by Mitchell et. al. The Canadian Mineralogist Vol. 36, pp.107-116 (1998).

The samples of Latrappite with clear dominance of Nb are from the "type locality" referred to as "Oka" and were collected by "employees of the St. Lawrence Columbium and Metals Corporation" on "property held by Columbium Mining Products Limited" These original samples are at the ROM. This would have been collected before the mine opened. However, they refer to some other samples from "Oka" in the article, but don't give a clear idea where those came from.

Samples from Husereau Hill and "The Bond Zone" were Perovskite.

One Perovskite, self collected from SLC mine dumps, FYI RRUFF ID: R110178, is Ti 42% Nb 39%... so that is pretty close to Latrappite... if you checked enough you would probably get one. However, I can think of better things to do...

28th Feb 2013 15:46 UTCLászló Horváth Manager

The type specimen was found in the Bond zone, across the valley from the St. Lawrence mine, long before there was a mine, as Don indicated. Recently analyzed specimens from the Bond zone turned out as both latrappite and perovskite. Perovskite is probably more common. Latrappite was also found (in the 1960s) in an apple orchard in the souther part of the complex.

Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 25, 2024 10:08:26

Go to top of page