Abernathiite is a mineral of the arsenate class with the formula K (UO2) (AsO4) · 3H2O. It is named after Jess Evrett Abernathy (1913–1963), who first found it in 1953 in the US state of Utah. It was described as a new mineral species in 1956. Abernathitis is yellow and occurs in the form of small crystals.
Description
Abernathitis is a transparent yellow mineral that occurs in the form of layered crystals up to 3 millimetres (0.12 inches) in size. The mineral has one perfect cleavage at {001}. Abernathitis fluoresces yellow-green in the long-wave and short-wave ultraviolet. Due to its uranium content, the mineral is radioactive.
Deposits and Formation
Abernathyite is formed as a coating on cracks in asphalt sandstone containing uranium deposits. The mineral is found to be associated with heinrichite, scorodite, and cheinerite. Abernathitis is known from France, Germany, Poland, South Africa and the United States.
Structure and formula
At the first description in 1956, the formula was identified as K (UO2) (AsO4) · 4H2O. However, only about 25 milligrams of the mineral was available for analysis, so a number of precautions were taken during repeated analyzes and using artificial mixtures. In 1964, a further study of the mineral revealed inconsistencies between the electron density subtraction maps and chemical evidence that abernatiite contains potassium. This led the authors to reconsider the formula as K (UO2) (AsO4) · 3H2O.
Abernathitis crystallizes in tetragonal syngony.
Story
Jess Abernathy was the operator of the Fuemol mine in Emery County, Utah. In the summer of 1953, he noticed yellow crystals covering the sandstone in the mine, which, in his opinion, could be mineralogically significant. Samples were sent to Grand Junction, Colorado, for study by E.B. Gross. He could not compare the optical properties of the mineral with any known species, so he sent samples to Washington, where there were corresponding opportunities for further research. Mineralogues A.D. Wicks and M.E. Thompson of the US Geological Survey studied the mineral on behalf of the US Atomic Energy Commission's Raw Materials Division.
Abernathitis was described in the journal American Mineralogist in 1956. The mineral was named Abernathite after the discoverer of Jess Abernathy. Samples are kept at the National Museum of Natural History in Washington, DC.
Mineral properties
Origin of the name: In honor of the owner of the Moab mine, Utah, Jess Abernathy, who found the first specimens.
Opening Place: Fuemroll Utah Mine, USA
Year of opening: 1956
Luminescence: Intense yellowish-green luminescence of LW and SW - rays.
IMA status: Valid, first described until 1959 (before IMA) 1956
Strunz (8th Edition): 7 / E.02-150
Strunz (9th Edition): 8.EB.15
Hey's CIM Ref .: 20.7.3
Dana (8th Edition): 40.2a.9.1
Molecular Weight: 520.11
Cell parameters: a = 7.176Å, c = 18.126Å
Ratio: a: c = 1: 2.526
Number of formula units (Z): 4
Unit cell volume: V 933.40 ų
Point group: 4 / mmm (4 / m 2 / m 2 / m) - Dietragonal dipyramidal
Space Group: P4 / ncc (P4 / n 21 / c 2 / c)
Radioactivity (GRapi): 3,480,240.22
Density (estimated): 3.572 g / cm3
Density (measured): 3.3 g / cm3
Refractive indices: nω = 1.597 - 1.608 nε = 1.570
Maximum birefringence: δ = 0.027 - 0.038
Type: uniaxial (-)
2V angle: measured: 5 °
Optical landscape: moderate
Form of selection: Thin crusts, rosettes of fine-grained and flaky discharge
Form of selection: granular masses
Classes on the systematics of the USSR: Phosphates, arsenates, vanadates
IMA Classes: Arsenates
Chemical formula: K (UO2) (AsO4) * nH2O, n = 3-8
Syngonia: tetragonal
Colour: Pale Yellow
Dash Color: Pale Yellow
Gloss: Glass
Transparency: Translucent
Cleavage: very perfect on {001}
Hardness: 2.5 3
fluorescence: Yes
Abernathyite is formed along cracks in asphalt sandstone containing uranium deposits. The mineral is found to be associated with heinrichite, scorodite, and cheinerite. Abernathitis is known from France, Germany, Poland, South Africa and the United States.
Abernathitis was described in American Mineralogist in 1956. The mineral was named Abernathite after the discoverer of Jess Abernathy. Model specimens are currently kept at the National Museum of Natural History in Washington, DC.