This is an educational post, directed towards folks new to the hobby. There has been discussion in our FB group lately about using cheapie 39Xnm flashlights for fluorescent minerals.
Rock collecting is a pretty easy hobby to get into - buy a hammer, find a pile of rocks, and you're rock collecting.
Minerals which are capable of this reversible color change by exposure to UV (or other energy sources), without any change in their essential composition, are said to be tenebrescent
Tugtupite is the most widely known fluorescent mineral from Greeenland. It is used in making beautiful tugtupite cabochons.
Perhaps the most famous mineral found in Greenland is tugtupite - and is certainly the main quest of those who travel to this remote area. Local villagers spend much of their free time in pursuit of this stone and many legends have risen around tugtupite.
This post was made over four years ago. Since that time it has become outdated. There is a new light - the Convoy FyrFly which is significantly brighter and a major next-generation of an already excellent light.
FyrFly Convoy C8 365nm UV Flashlight - The Next Generation Convoy - an Original Design by Group Cons
Reinventing the Convoy for the Fluorescent Mineral hobby
Buy only from trusted dealers and manufacturers.
I'm not sure how many people have built the 18 watt SW conversion from Mark Cole's plans on MinerShop, but if you did or intend to do so, here's mine I've finally completed.