This specimen consists of raspberry red, octahedral spinel crystals in a white marble matrix, from the An Phu Marble Mine, Luc Yen, Yenbai Province, Vietnam. Under long wave UV, the spinel fluoresces deep, rich, red, and the marble matrix shows a moderate blue/white response. Not all red spinel is created equal in terms of fluorescence. Some fluoresces dimly, or not at all. This is a particularly bright fluorescing specimen. Size 36 x 32 x 24 mm, 25 grams.
Under long wave UV (365 nm), the spinel fluoresces a luscious, cherry red color, while the marble matrix shows a contrasting blue/white response.
Same specimen shown under visible light.