Hello, Judy. It sounds like your son has a long wave blacklight. This type of light is great for minerals such as fluorite, calcite, strontianite, hyalite, and wernerite, and clothing made of cotton. You ask about seeing different colors other than purple. Here's where it gets tricky. Purple is not a fluorescent color. What you are seeing is the violet edge of white light (think rainbows) that it directly next to the long wave ultraviolet light band which is invisible to human eyes. When you see fluorescent colors, you are seeing the reaction of electrons emitting light rather than reflecting light.

The minerals your son are looking at either 1) are not fluorescent; or 2) are fluorescent only under a short wave black light. Unfortunately, you are right that you would need to invest in a much more expensive short wave UV light to see the colors, if your minerals are short wave reactive. Some short wave minerals are calcite, willimite, and chalcedony.

This was very basic, but I hope it helped you.

Regards, John

From John - May 13, 2008 at 08:00:53
Email: marine7812[ ]yahoo.com

Message: 66511