You guys have got me thinking about this waxing leather thing, since I have never done it, and am about ready to make a sheath for a kit knife I am working on. So, I did some googling, and came up with this bit of info:

"Wax has a low melting point. To keep your waxed leather from "melting" in the sun, add about 3 tablespoons of stearine (sic) to each pound of wax. You can buy a bag fairly cheaply at MJ Designs. It makes the wax harder, melt at a higher temperature (eliminating wilted leather) They also sell crystals, but if you can get it, use the powder, it dissolves completely."

Never heard of Sternin(e) before, so I googled it to find out what it is:
"Stearin...is a glyceryl ester of stearic acid, derived from animal fats created as a byproduct of processing beef. It is used as tallow in the manufacture of candles and soap..."

Now, assuming that it does as described, I've gott figure out where to buy it...