Although Glitch`s apparatus is clearly an ultra-violet nitrogen laser, there remains some doubt as to his observations. My replication of the set-up, using modern materials, showed no laser induced fluorescence with Heights Mine green fluorite. The spar crystals exhibit strong fluorescence in both sunlight and the broad-band UV from the spark-gap. The coherent output of the laser, producing strong fluorescence on copier paper (because of it`s 'whitening' chemical treatment), shows only a faint purple glow on the fluorite. This remains when a 337.1nm blocking filter (sheet of polycarbonate) is introduced. The glow therefore is simply the visible light emission from corona discharge along the discharge gap.
The coherent UV from the laser has yet to be tested on the full variety of crystals from Heights Mine in my possession. The mine produced fluorite in an unprecedented variety of colours, with considerable banding (phantoms) produced by various rare-earth impurities such as Europium. Perhaps the crystal (supposedly!) used by Glitch was unusual, even for this world renowned mineralogical site.
At present (28th Aug `02) I am optimising the design of my version of Glitch`s laser. An article on this design (which can be built for less than £10 including the hand operated power-supply) will be published on-line soon. Similarly, an article about Heights Mine is on it`s way. Hopefully, by then, I`ll have tested my complete collection of fluorite crystals from the locality (from colourless ice-clear, through purples to apple-greens) with the laser.
A currently operating fluorite mine a few miles from Heights Mine is producing extremely fluorescent specimens. The Rogerley Mine in Weardale UK has an excellent website. Specimens are available (I`m not associated with the Rogerley Mine) should any nitrogen laser enthusiasts wish to try Glitch`s experiments.