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Mckelveyite-(Y) Donnayite-(Y) & Phillipsite-Na

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LMB169737

Mckelveyite-(Y) Donnayite-(Y) & Phillipsite-Na

Type Locality
Analysed

Description Tabs

Description
Locality: 
Poudrette Quarry, Mont Saint-Hilaire, Québec, Canada
Class: 
Crystals on Matrix
Size Range: 
Thumbnail (1-3cm)
Size: 
1.5 × 2 × 1.5 cm
Largest Crystal: 
0.08cm
Weight: 
14.00gr
Description

MSH is the type locality for donnayite-(Y). It is uncommon, but not rare here. Mckelveyite-(Y) is rare. However (as is generally the case at MSH) this is neither “end member” donnayite-(Y) nor “end member” mckelveyite-(Y). As shown in the EDS scan (see the “Analysis” tab), significant Ba and Sr are both present. While peak heights can not be directly compared in a qualitative scan such as this, it does suggest that mckelveyite-(Y), rather than donnayite-(Y), might be the dominant component. 

Note: This is not the specimen that was analyzed, but it is from the same find and looks identical to it.

In the present case, the “crystal” (0.75 mm) shown in the first pair of photos appears to be composed of many many smaller, “saucer” shaped, crystals. This sort of epitaxy is also known from Kukisvumchorr (Kola). (See the article referenced under the "Analysis" tab.) Also shown in the first pair of photos are two of the many aggregates of phillipsite-Na on the specimen. They each span about 1 mm. Phillipsite is very uncommon at MSH.

The second pair of photos (FOV 2.2 x 3.6 mm) shows a larger (1.5 mm) phillipsite aggregate and a smaller (0.5 mm) mckelveyite/donnayite “crystal”.

The third pair of photos shows the largest phillipsite aggregate which spans about 2.3 mm.

As for the presence of Fe and S, it is not clear if this is coming from some admixed FeSO4 compound or from tiny pyrite specks (some of which can be seen scattered on the matrix).

In any case, a very interesting specimen. But you will need about 30X to view the crystals clearly.

Single item shipping weight 2.9 oz. Outside the USA, the stated postage and packing rate applies up to a total weight of 8 oz (225 g).

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

Mckelveyite-(Y)

Formula: 
NaCaBa3Y(CO3)6·3H2O
Strunz: 
5.CC.05
Hardness: 
3.5 - 4.0
Type Locality: 
Diamond Alkali Daco No. 3, Green River Formation, Sweetwater Co., Wyoming, USA

Donnayite-(Y)

Formula: 
NaCaSr3Y(CO3)6·3H2O
Strunz: 
5.CC.05
Hardness: 
3.0
Type Locality: 
Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry; Carrière Mont Saint-Hilaire), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada

Phillipsite-Na

Formula: 
(Na,K,Ca0.5,Ba0.5)4-7[Al4-7Si12-9O32]·12H2O
Strunz: 
9.GC.10
Crystal System: 
Monoclinic
Hardness: 
4.0 - 5.0
Colour: 
White
Streak: 
White
Type Locality: 
Rupe di Aci Castello, Aci Castello, Etna Volcanic Complex, Catania Province, Sicily, Italy
Analysis
Analysis Report - only: Mckelveyite-(Y) Donnayite-(Y) & Phillipsite-Na

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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