Anatomy of a Mineral Specimen

Mineral Matters #463

I dug out a small specimen today that has been in my collection for over 30 years. It comes from from the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada. It turned out to be very interesting and has components of the old Hidden Collection throughout.

The label only states thomasclarkite-(Y), molybdenite and elpidite. A yellow arrow points to thomasclarkite and elpidite.

It consists of greyish-green prismatic spray of crystals of elpidite, pale yellow platy thomasclarkite, silver hexagonal molybdenite, tiny brown siderite, green prismatic aegirine, sodalite(?), quartz(?), all in/on white albite, and with a couple of unknown species too.

Click on the images for a higher resolution version.

Below: Elpidite (green fluorescence) under shortwave ultraviolet light. Width of view 4.5mm.

Below: Grey-green elpidite (centre), silver metallic molybdenite, darker green prismatic aegirine (on right), hexagonal prisms of quartz(?), on white albite. Width of view 4.5mm.

Below: Platy thomasclarkite-(Y) in the centre of the photo and elsewhere, molybdenite, elpidite on the left, on albite. Width of view 3mm.

Below: Unknown black mineral on what looks like albite under white light. Width of view 9mm.

Below: Sodalite? (orange fluorescence) under longwave ultraviolet light. Width of view 9mm.

Below: Albite (blue fluorescence) under mediumwave ultraviolet light. Unknown orange fluorescence. Width of view 9mm.

Below: Albite (magenta fluorescence) under shortwave ultraviolet light. Unknown orange fluorescence. Width of view 9mm.