Lithium occurs in spodumene, lepidolite, petalite, eucryptite. Spodumene is the most common and important of these. Spodumene usually fluoresces orange/tan/pink under long wave UV light, 365nm being the optimal wavelength. It can fluoresce other colours (rarely), as can Lepidolite and Petalite. Eucryptite fluoresces a deep cherry red under short wave UV.
[Long wave UV is also known as UVA and Short wave UV is also known as UVC]
Several of our 365nm FL8 torches are being used to find spodumene in Western Australia.
The brightness and colour of a given mineral’s fluorescence depends on the impurities in the mineral. Those impurities are called “activators”. Different activators in the same mineral can cause different colours of fluorescence. Too much or too little activator in a normally fluorescent mineral can cause it not to fluoresce at all, or to fluoresce only dimly.
Therefore, it is not possible to use fluorescence to definitively identify minerals, but it can help confirm an identification. For example, if you are looking for a mineral in an area where it is known or likely to exist, and you find the expected colour of fluorescence, there is a high probability that you have found what you are looking for.
The video shows spodumene (18cm x 10cm) from a mine in WA fluorescing under an FL8 torch.
Initially the torch is about 3m from the rock, then about 2m and finally about 1m.