I think that's the wrong kind of chalk. Gymnasts and weight lifters use magnesium carbonate chalk. I am thinking about trying that as I used to use it for weightlifting back when I was younger. I'll try to remember to let folks know if it worked or not.
Good information, sir. Magnesium carbonate is indeed one of the main ingredients in Yonex's Grip Powder. It has a distinctive smell/fragrance to it.
Magnesium carbonate does work well to improve your grip. Bad thing is when it gets wet and dryes it turns into something that reminds of cement.
IME chalk is used more for "traction" than "tack", but it should work reasonably well for a racket grip. Go for resin if you want tack as well.
So I have now finished experimenting with using magnesium carbonate chalk on my grip (towel). It seems quite effective in the short run for making the grip dry and easy to handle. However once the grip gets a lot of chalk in it, it dries very hard. After drying hard, you have to dispose of the grip; otherwise you might get blisters etc. In short it seems if the grip is on it's last legs, chalk is pretty useful. Otherwise it's not worth it as you will want to get rid of the grip. I'm not sure how it compares to grip powder. That is much to expensive for such a small quantity in my opinion. If it is pretty much the same I could see why pros like it. It keeps your grip dry in the middle of a game and they are going to dispose of their grip after the game anyway (all their equipment is free or close to it). So they get the benefits but not the cost.