- It has a zero. The sides are numbered zero to nine instead of one to ten like you might expect. (Although the zero is often treated as ten in play.)
- You can use multiple d10s to simulate a d100, d1000, etc.
What I don’t care for is the shape, which is termed a pentagonal trapezohedron.
If I had to pick a favorite from among my dice, it might well be this one:
It is the d20—twenty-sided die—from my second set of polyhedral dice. Things I like about it:
- It’s a precision die from Gamescience, which I find aesthetically pleasing.
- Like almost all d20s, it is a regular icosahedron, one of the platonic solids, which I find aesthetically pleasing.
- Unlike almost all d20s made today, it is numbered from zero to nine twice, so it can be used as a d10 and shares all the things I like about d10s.
- Unlike the earliest d20s, which were numbered in the same fashion, half of the faces have a plus sign, so it can be used as a d20 without using a second die or using two different colors for the numbers.
It was unique among my dice. Well, almost. I also have a “diamond” (i.e. clear plastic) one purchased at the same time, but it is hard to read no matter what color you use for the numbers.
I’m not sure if they still make these. The newer Gamescience dice sets I have bought have come with 1–20 d20s. It turns out, however, that Gamestation does sell some of these “d20+” dice, which I suspect are NOS. So, I ordered some. My favorite die now has some competition.