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Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite

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LMB608594

Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite

Very rare at MSH
Analysed

Description Tabs

Description
Locality: 
Poudrette Quarry, Mont Saint-Hilaire, Québec, Canada
Class: 
Crystals on Matrix
Size Range: 
Small miniature (3-4.5 cm)
Size: 
1.7 × 3.2 × 1.5 cm
Weight: 
7.00gr
Description

This unimposing specimen actually has several very unusual and interesting features, not the least of which is verified columbite-(Fe) – a very rare mineral at MSH. Caveat: Only qulaitative EDS was used. While the Fe peak looks "substantially" higher than the Mn peak, comparison of peak heights is risky for such scans. Also, while two out of three samples from this find showed Fe > Mn, a third sample showed Mn > Fe.

In addition to the columbite, there are two good sized gobbinsite aggregates, several “rosettes” of gmelinite-Na (some possibly altered), and complex, flattened, crystals of siderite inter-layered with muscovite, some of it in the form of octahedral stacks, mostly with hollow interiors. Presumably the latter are PSM. (See the “Analysis”  tab for some of the scans.) Bottom line: This is a most unusual specimen from the famous Poudrette pegmatite. 

The first photo (FOV 2.2 x 2.1 mm) shows the broken columbite crystal ( max diameter 0.9 mm) that was analyzed. Another analyzed specimen from this find had complete, free-satnding, euhedral crystals of columbite, but it seems that many, if not most, columbite crystals at MSH are embedded and thus unlikely to survive exposure.

The second photo (FOV 2.5 x 1.65 mm) shows the other, partial, columbite crystal (0.85 mm). This one was not analyzed – it’s not practical to analyze everything!

The third photo(FOV 3.6 x 2.5 mm) shows one of the gobbinsite aggregates (2.5 mm) and a somewhat altered looking rosette of gmelinite-Na (2.1mm).

The next pair of photos (FOV 4.55 x 5.65 mm) shows some of the flattened siderite crystal, the other gobbinsite aggregate (2.3 mm) and some of the yellowish/tan muscovite. Note especially the muscovite “octahedron” (0.75 mm) at bottom center. There are several others on the specimen. (This is the most distinctly octhaderal looking one.)

The next pair of photos (FOV 4.5 x 5.8 mm) shows another altered gmelinite rostette (top right) along with strangely inter-layered siderite and muscovite. I’m not sure if the roughly circular object at bottom left is another hollow muscovite PSM or a ‘bottom”view of more of the altering gmelinite.

The last pair of close-up photos (FOV 4.3 x 6.7 mm) shows more of the inter-layered siderite and muscovite. The siderite crystal attop center is 1.9 mm wide.

There is also some pyrite on the specimen. Some other specimens from this find have chalcopyrite (rare at MSH), but EDS for this specimen showed pyrite for the analyzed speck..

Single item shipping weight (with TN case) is 3.3 oz (92 g). For shipments outside the USA, up to a total weight < 8 oz (225g), this can be combined with items from this or other auctions for the same postage.

Within the USA, postage now varies by destination. For total weights up to 13 oz, it ranges from $4.50 to $7.00 (including packing etc). Above 13 oz (up to 16 oz), I will use “own box” Priority Mail. The rate, including packing, varies from $8 to $10.

Mineral Data
What's on the rock

Columbite-(Fe)

Formula: 
FeNb2O6
Strunz: 
4.DB.35
Hardness: 
6.0
Type Locality: 
Green's Well pegmatite (Green's Tank), Pilgangoora, Wallareenya Station, Port Hedland Shire, Western Australia, Australia...

Gobbinsite

Formula: 
Na4(Ca,Mg,K2)Al6Si10O32·12H2O
Strunz: 
9.GC.05
Hardness: 
4.0
Type Locality: 
Hills Port, Gobbins, Island Magee, Co. Antrim, Northern Ireland, UK

Gmelinite-Na

Formula: 
(Na2,Ca)[Al2Si4O12]·6H2O
Strunz: 
9.GD.05
Crystal System: 
Hexagonal
Hardness: 
4.5
Type Locality: 
Nero Mt., San Pietro, Montecchio Maggiore, Vicenza Province, Veneto, Italy

Siderite

Formula: 
FeCO3
Strunz: 
5.AB.05
Crystal System: 
Trigonal
Hardness: 
3.5 - 4.5
Streak: 
White

Muscovite

Formula: 
KAl2(AlSi3O10)(OH)2
Strunz: 
9.EC.15
Hardness: 
2.5
Streak: 
White
Analysis
Analysis Report - only: Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite
Analysis Report - only: Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite
Analysis Report - only: Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite
Analysis Report - only: Columbite-(Fe) With Gobbinsite Gmelinite-Na Siderite & Muscovite

Seller Information

Payment options: offline, paypal_wpp, paypal_wps

Seller's terms and conditions

In addition to the standard terms and conditions, please note the following. Almost all IDs are visual. While in most cases the ID is obvious, there may be cases where it is not. If you are doubtful about a particular ID, please ask for more information. Or do not bid! Similarly, if you are not sure that the specimen meets your criteria, do not bid. I have tdone the best I can with the photos. Nevertheless, if you are not happy with a specimen for any reason, I will refund the bid price – but not the shipping costs (unless the fault is clearly mine) – if the specimen is returned. This policy applies even if analysis of the specimen shows that my ID was incorrect. When in doubt, ask - or don’t bid. Note that most crystals at MSH and Varennes are micros - even if on large specimens. Please pay attention to the stated sizes. Any customs duties, fees etc. are the responsibility of the buyer.

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