Yes they are edible, because they are formed naturally from earth without any added chemicals to change or alter the appearance of how they look.
Why are the so many different name of chalk?
Chalk names are derived from where they are mined example Belgorod Chalk are from the Belgorod region of Russia, so as New Oskol Chalk from Novy Oskol a town in Russia
Does all chalk have different taste?
Yes most do , some can be earthy, some may contain a bit of grit, some may be creamy. It depends on your preference, chalk are really subjective, one person might like the taste, and the other dislike the taste
Are they any effect of eating chalk?
Yes they are, you can have constipation if you do not drink enough water.Maintain a good diet, and eat in moderation.