Bou Beker, Touissit-Bou Beker mining district, Jerada Province, Oriental Region, Morocco Tarnowitzite, a lead bearing variety of aragonite. Some say that tarnowitzite is a mix of aragonite and cerussite. It fluoresces white under shortwave and pale yellow under longwave UV light. Longwave fluorescence. Images Copyright Simone Conti ..read more

This interesting and unique fluorescent specimen looks like something you'd expect to find in an underwater coral reef. Collected from the SK Star Claim #2 in Utah's Thomas Range in Juab County, this piece consists of a coralline aggregate of chalcedony and fluorite (verified by XRD analysis), coated with a brightly fluorescent layer of hyalite opal. This specimen was collected by the claim owner, Shaun Rasmussen, some time between 2015-2018. The size of this specimen is 93 x 83 x 45 mm, and it weighs 113 grams. In the above photograph, taken under long wave UV (365 nm), the hyalite shows a b ..read more

This material is known as "watermelon calcite" or "watermelon rock" due to its colorful red and green fluorescent response under UV. This flat specimen consists of pale yellow calcite sandwiched between two layers of light grey chalcedony. Under short wave UV the chalcedony fluoresces green and the calcite layer red/orange, giving the appearance of a succulent piece of watermelon. This specimen was collected from the Buffalo Gap Grasslands, near Weta, in Jackson County, South Dakota. It measures 120 x 66 x 18 mm and weighs 196 grams. Under short wave UV (254 nm), the middle calcite layer fluo ..read more

This unusual fluorescent specimen consists of crystals of honey-brown selenite sandwiched between two layers of light grey chalcedony. This specimen is brightly fluorescent under mid wave UV, but only shows a weak response under short and long wave UV. This specimen was collected in the area of Hay Springs, Sheridan County, in northwest Nebraska. This specimen measures 15.6 x 8.6 x 5.1 cm, and weighs 670 grams. The photograph above shows fluorescence under mid wave UV (302 nm). The selenite fluoresces a burnt orange color and the surrounding layers of chalcedony fluoresce bright green. The gr ..read more

Red trinitite is technically not a true mineral, because it was not formed through a geologic process. Rather, this brick-red colored glass-like material was created at 5:29 A.M. Mountain Time on July 16, 1945 in the superheated blast fireball of the test of the first atomic bomb in Alamogordo, New Mexico. The atomic blast was so hot that it melted the surrounding desert sand, turning it into glass. Trinity was the code name for the first atomic test, hence the name "trinitite" for this material (for more on the Trinity test, see the 2023 release "Oppenheimer" movie). Green-colored trinitite ..read more

365nm UV light is often called "blacklight". Before the advent of LW LEDs, blacklight fluorescent tubes, (the kinds used in hippie days to light up psychedelic posters) were the standard LW light for our hobby. They were not very powerful but they did light a large area. The "black" glass, really a deep violet, acted as a filter. It allowed UV, usually 365nm, to pass through but blocked most of the bright whitish light the fluorescent bulb produced. I say "most" because a lot of violet/purple light still escaped, illuminating our rocks with a violet tint, not the best. Additionally, since thes ..read more

Specimens like this are mostly sold as green and purple sodalite, but most are massive pieces. This piece contains part of a crystal that reveals what happened. The green is the first to crystalize. In a later stage it is covered/surrounded by a layer of photochromic sodalite. The green is fluorescing very vivid orange (365 nm), the purple a lot weaker and it also shows the typical white fluorescence (310, 275 and 255 nm) and afterglow. The spectra tell us more. Both parts show the orange fluorescence from the S2- ion. But the green mineral has the typical hauyne spectrum, while the purple sh ..read more

Yellow fluorescent aragonite due to organic impurities and possible lattice defects. Red fluorescent calcite showing Mn2+ and Ce3+-OH complex emission. Black full: 365 nm, black dashed: 275 nm, grey dashed: 255 nm excitation ..read more

Rhombohedral calcite group, Beez, Namur, Belgium. It exhibits the typical yellow-green fluorescence and afterglow (PeL image). At shorter excitation wavelengths, the colour becomes more greenish due to a shift in emission maximum. Black full: 365 nm excitation. Blach dashed: 275 nm excitation ..read more

Yellow calcite skalenohedra on a layer of irridiscent pyrite in septaria, Kontich, Atwerpen, Belgium. The white fluorescence (365 nm LED excitation) is coming from a strong emission in the blue part. Most probably caused by lattice defects, although organic acids are also a possibility since septaria grow in clay close to the surface ..read more