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

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LMB588891

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

Analysed

Description Tabs

Description
Locality: 
Poudrette Quarry, Mont Saint-Hilaire, Québec, Canada
Class: 
Crystals on Matrix
Size Range: 
Micromount (under 1cm)
Size: 
0.5 × 0.8 × 0.8 cm
Description

The first pair of photos shows an amusing “potted” phillipsite-Na, the pot being mckelveyite-(Y) and donnayite-(Y), probably syntactically inter-grown. FOV is 2.3 x 2.7 mm, the “pot” is 0.8 mm wide, and the phillipsite “plant” spans ca 1.7 mm. Note that the mckelveyite/donnayite “crystal” appears to be composed of many smaller, “saucer” shaped, crystals. This type of epitaxy is also known from Kukisvumchorr (Kola).

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. A much fuller discussion of the ID is given under the “Analysis” tab (it gets messy). (To make the discussion legible, click on the bottom image.)

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

The second pair of photos shows the “top” of almost the entire specimen. FOV is 4.5 x 6.2 mm. Note that there is another mckelveyite/donnayite “pot” on the right, and another phillipsite “plant” at the bottom.

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

Single item shipping weight 2.7 oz (76 g). Outside the USA, the stated postage and packing rate applies up to a total weight of 8 oz (225 g).

Within the USA, there is a nominal increase of $0.20 for each additional ounce. Above 13 oz, I will use Priority Mail. Up to 16 oz, the “own box” Priority rate is $9.25 (including packing).

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) With Phillipsite-Na
LMB minerals

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.