Little cluster of well formed scheelite crystals. Dark colored in daylight, they fluoresce the typical bright blue under shortwave UV light and a quite nice orange/red under midwave UV light (a bit overexposed in the photo…). The blue shortwave fluorescence is intrinsic in scheelite, due to the tungstate group (WO42-), while the orange/red fluorescence under midwave is most likely due to REE impurities activators.
From: Chenzhou, Hunan, China.
A small thumbnail: 2.0 x 1.5 x 1.5 cm, 9.38 g.
MinID: TER-NMN
Scheelite (MW)
Midwave Fluorescence
Scheelite (SW)
Shortwave fluorescence
Scheelite (vis)
Normal light