[iso]

I am looking for a non-abrasive phosphoresent powdered chemical.This chemical will be carried with liquid wax.  It has to be fairly stable, and safe for handling (i.e., no dangerous dusts) and environmentally safe (if possible).  If anybody could help me out in finding one I would greatly appreciate it!

[Enthalpy]

Welcome, iso!

Paper and cotton are not very abrasive and can be chopped to fine powder. They fluoresce already with 405nm light from so-called UV-Led-flashlights, which you could use to try a few materials around you.

Then you have classical fluorescent compounds, which other people here know better.

[Enthalpy]

Some polymers too fluoresce. Try on clothes: it could be polyester rather than polyamide. This polymer too can be chopper to fine powder.

The reemitted colour is white, like for cotton and paper.

[Enthalpy]

Oops, I suggested fluorescent materials, iso wanted phosphorescent ones. Sorry!

[Enthalpy]

Only from Wiki https://en.wikipedia.org/wiki/Phosphorescence
aluminates are expected to be abrasive. Calcium sulphide should be less brutal.

Maybe strontium aluminate powder could be covered by a thin layer of softer material? Something like HOSi(CH₃)₃ maybe? Or just plain silicone (polydimethylsiloxane PDMS), which adheres well on ceramics and is soft and transparent?

No idea if some organic materials phosphoresce. I hope more knowledgeable people will jump in.