Pica😩 - craving chalk!

Chanler
I know the reason behind it is pica which is "common" during pregnancy but it's still really strange.
I'm always craving- but haven't eaten- chalk. (Although it would hypothetically be non toxic and my doctor said it wouldn't harm me) It's my strongest craving because I don't fulfill it.
I'm glad I'm not craving like laundry detergent or dirt but I still feel pretty crazy. 
So I'm going out on a limb here but anyone craving anything super weird like this?