If you have a bathroom scale, a drill press and a micrometer, you can measure the Brinell Hardness easily.
The point needs to be 1/4" round, like a ball bearing. Brinell actually created this standard using a 7/16" ball bearing.
You just apply 200 pounds of force through the drill press into the lead, and measure the diameter of the indentation. The larger the indent, the softer the material. The force is not critical, so +/- 10 pounds doesn't change much.
I even made a point, and put it into a file handle. If I press as hard as I can it's around 200 lbs. I use this at the junkyard to see how hard the lead he has is.