ME91AL8: Twinned crystals of Gypsum, transparent, very bright and with a color between yellow and orange. Implanted in a spheroidal aggregate of lenticular crystals of the same Gypsum but with a black color, possibly due to organic inclusions. The yellow crystals also have the peculiarity that they show not only fluorescence but also phosphorescence when exposed to ultraviolet light.
Red River floodway, Winnipeg, Winnipeg Capital Region, Manitoba  Canada (1996)

Specimen size: 10.7 × 8 × 6.4 cm = 4.21” × 3.15” × 2.52”

Main crystal size: 4.6 × 3.5 cm = 1.81” × 1.38”