First off, it is a bad idea to use any kind of sand with a young leo. You need to use paper or paper towels until they get old, because they will injest the sand and it will mess them up.
If when your leo is older you want to go with sand, which most people still recommend steering clear of because of problems with impaction etc.., They recommend very fine playground sand, this way there is less chance of it getting stuck in their tummies.
Stay away from calcium sand, studies have shown that 70% of that stuff stays in their systems. It is not good for them, it is not fine grain, and the colored sand will die your leo's feet. I adopted a leo that was being kept on green calci sand and his toes have been green for several sheds. I hope this helps. If you read several leopard gecko care sheets, you can find more information about the substrates that are recommended.
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~~Tania~~
1.0 Chinese Water Dragon - Jake
1.1 Leopard Geckos - Chorky and Gilbey
1.0 Maltese Shi Tzu Mix - Mosley
RIP 1.1 Med. Geckos - Mary and Peter