Updated: Apr 1, 2020
The Minerals Fluorescence All minerals are made up of atoms organized in crystal lattices which are held together by the forces and energies of the structure. Atoms are surrounded by a number of electrons (different for each type of element). If this structure is subjected to a ray of ultraviolet light, the electrons absorb the energy sent (ionization) and jump to more external orbits of the system.
Scheme of how the electron is ionized and then loses its energy in the form of visible light (source). However, this new electron position is unstable and within a short time the electron returns to its previous orbit. This second step generates the loss of energy in the form of electromagnetic radiation with a visible light wavelength. For this reason we can see a completely different color from what we see in natural light and for this reason the fluorescence in most cases decays almost immediately after turning off the lamp. Below you can see the division of the electromagnetic spectrum by the wavelengths of ultraviolet rays (long UVA - medium UVB - short UVC).
The lamps that emit this type of light are of two types: long wave (Long Wave UV) and short wave (Short Wave UV). The former is very easy to find and emits radiation at around 360-380nm, while the latter needs a very expensive and more difficult to find filter and the wavelength is around 254nm. Pay attention that prolonged exposure to UV rays can damage your skin and generate tumors. So it is always a good idea never to point the lamps towards the body and not to stay with your hands for too long under their action. Here are some examples of UV lamps and one of our display cases.
Long wave UV lamp.
Short wave UV lamp, to which a filter must be applied to have the right wavelength (the filter is very expensive, while the tubes are not).
The case is wooden and black colored internally. The tubes are fixed inside the upper panel and externally we have provided a plexiglass plate that shields a small part of the rays (be careful: these panels do not protect you from UV rays; UV rays are harmful !!!)
Long Wave UV
Calcite, Aragonite, Acmanite, Quartz, Aragostronzianite, Fluorite, Manganocalcite, Scapolite.
Quartz from La Sassa (see also article "La Sassa Quartz").
UV Short Waves
Franklin minerals, Halite, Opal.
Calcite, Aragonite, La Sassa Quartz, Scapolite.
Calcite of Campiglia Marittima. Finally, a very interesting tool that has arrived on the market in recent years is the LED long wave UV torch. It is light in weight and very powerful and therefore very useful to carry in your pocket. (Taken at the fair in Monaco at a price exceeding € 100!)