Home > Burmese Minerals – May 22 > MS1333 Fergusonite-(Y)
Fergusonite-(Y) - Sold
- Kyauk Pyat That
- Mogok Stone Tract
- Mandalay Region
- Burma
- 3.1 by 0.5 by 0.5 cm – Thumbnail specimen (fits into a 2.5 cm cube)
The mineral name fergusonite-(Y) honors Sir Robert Ferguson (1767-1840), landowner, politician, and mineral collector in Scotland (Haidinger, 1825). Ferguson's collection remained intact until 1997, when Brian Lloyd purchased the collection.
Fergusonite-(Y) is nominally a yttrium niobium oxide, but samples typically contain tantalum, other rare earth elements and uranium. In fergusonite-(Y), a minor uranium content causes damage to the atomic arrangement of fergusonite-(Y), leading to a loss of crystallinity. The mineral becomes amorphous in a process known as metamictization. Recognition of fergusonite-(Y) therefore depends on combining chemical analysis with study of its external crystal form.
This is a long prismatic crystal, showing crude crystal form. The terminations appear to be very rough pinacoids on a twisted tetragonal prism. The mineral shows superficial brown alteration, itself being resinous black on a fresh surface. There is a bit of adhering clay.