Powdered gelatin or granulated gelatin is not leaf gelatin or sheet gelatin. It is by far the form most widely available in this country, being available in just about every grocery store and supermarket. And we have no idea what commercial gelatin powder mix before it is made into gelatin is.owdered gelatin or granulated gelatin is not leaf gelatin or sheet gelatin. It is by far the form most widely available in this country, being available in just about every grocery store and supermarket. And we have no idea what commercial gelatin powder mix before it is made into gelatin is.