Formula: NaNd(SO4)2(H2O)
Sulphate, neodymium-bearing mineral
Crystal System: Trigonal
Specific gravity: 3.436 calculated
Hardness: 2½ to 3
Streak: White
Colour: Colourless
Luminescence: No fluorescence under UV

Sedimentary environments
Hydrothermal environments

Chinleite-(Nd) is a new mineral, approved in 2022 and to date (August 2023) it has been reported only from the Red Canyon Mining District (two localities).


At the type locality, the Markey mine, Red Canyon Mining District, San Juan County, Utah, USA, the uranium deposits occur within the Shinarump member of the Upper Triassic (237 to 201.4 million years ago) Chinle Formation in channels incised into the reddish-brown siltstones of the underlying Lower Triassic (251.9 to 247.2 million years ago) formation. The Shinarump member consists of medium- to coarse-grained sandstone, conglomeratic sandstone beds, and thick siltstone lenses. Ore minerals, such as uraninite, montroseite and coffinite, were deposited as replacements of wood and other organic material and as disseminations in the enclosing sandstone.
Since the mine closed in 1982, oxidation of primary ores in the humid underground environment has produced a variety of secondary minerals, mainly carbonates and sulphates, as efflorescent crusts on the surfaces of mine walls.
Chinleite-(Nd) is a very rare mineral in the secondary mineral assemblage. It occurs on asphaltite in association with gypsum and natrozippeite, as prisms up to about 0.3 mm in length and 0.1 mm in diameter. The rare-earth elements probably existed in the sandstones of the Chinle Formation prior to the deposition of the uranium ores (CJMP 61.2.411-418).

Back to Minerals