chalk is a white soft material
I remember having to use that instead of dry erase markers.
chalk is a form of limestone
I had no idea, I thought limestone was totally different.
chalk is a mineral form of calcite
I don't really know what calcite is apart from the fact that it is a mineral.
its a white for of mineral calcite which is similar to calcium
Hmm so like our bones then? Must be a lot softer than that though.