Note: Rinkite vs mosandrite has a long and convoluted history at MSH, less so at the Demix quarry. In 2016, the IMA added "-(Ce)" to both species names, and both are currently on the valid species lists for the localities. The Demix specimen has not been analyzed. The MSH specimen was analyzed via EDS, but EDS might not be sufficient to distinguish rinkite-(Ce) from mosandrite-(Ce) - the species differ mainly in the presence or absence of Na, which is hard to detect and often easily lost. Hence "rinkite" should be taken to mean "rinkite group".
This is a lot of two specimens of rinkite of rather different habits. The dimensions given are for the first specimen, which is from the Demix-Varrenes quarry in the Saint-Amable sill, and is associated with well-formed eudialyte (proper). The second specimen is from the Poudrette quarry at Mont Saint-Hilaire. It is 2.4 x 2.4 x 1.3 cm and weighs 9 g. (The two localities are less than 20 km apart near Montréal, Québec.)
Rinkite is relatively common in the Saint-Amable sill, but it does not look much like rinkite from MSH or other localities. Raggedy, sometimes curved, plates, growing in a sort of “whirligig”, are typical of the rinkite found here. The best plates have a rectangular shape, but most of it looks like shredded lettuce – as shown in the first pair of photos (FOV 2.5 x 3.6 mm).
On this specimen, the rinkite is associated with thick tabular eudialyte as shown in the second pair of photos (FOV 3.1 x 2.4 mm). The eudialyte spans 2.2 mm, with individual tabular crystals ca 0.8 mm.
The next photo (FOV 5.6 x 4.1 mm) is a broader view showing both the rinkite and the eudialyte.
Note that eudialyte proper is the only verified eudialyte group mineral at this quarry, hence my ID. (Possibly there is a manganoeudilyte like “mineral” – but not manganoeudylite – here. However, the crystals have not been suitable for a description.)
While eudialyte is common at this quarry, unbroken crystals, such as these, are not. The crystals are extremely brittle.
The rinkite on the second specimen was identified at the ROM as probable rinkite/mosandrite using EDS. The close-up photos both show radiating aggregates 5.9 mm in maximum diameter. The rinkite is embedded in very dark purple fluorite with - large for MSH - embedded fluorapatite. A rather peculiar assemblage. In addition, analysis of the yellow-green band below the rinkite bearing layer resulted in a mystery. You can have fun trying to figure out what it might be. (See the “Analysis” tab.)
This specimen is ex Ron Waddell and dates from 1976.
Combined shipping weight 2.8 oz. 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 (including packing) is ca $9.25 (varies by destination).
