Crystals growing in possible salt dough

[bluetack45]

You know when you get games such as Cranium or any others that involve acting or making something, they often come with a modeling dough that you can use to create your ideas with.
I got such a dough in such a game. It was about a year and a half since we last played the game, myself and my family but when we opened the dough we discovered that it had not only hardened, rock solid, but it also had grown crystals.
Clear angular crystals all over the surface of the dough. They are very hard to get out and examine as the dough is so hard. I've had my fair share of experience with crystals, I've grown many and entered and won competitions on a few occasions, but I have never seen anything like this.

What I want to know is, are these salt crystals in some sort of salt dough, or if not, what else could have caused crystals to grow like this. Any ideas?

[deleted-93346]

Very observant of you bluetack45.

I haven't a clue what these crystals are. However, you might get some ideas from

http://en.wikipedia.org/wiki/Modeling_clay

Good luck exploring this interesting phenomenon! I'm curious what you will discover.