Nether sand

The nether sand is a sand type colored like soul sand and soul soil but cannot be found in the Nether or any dimensions.

Fire doesn't turn into soul fire if placed on nether sand. You can also transform nether sand into glass.

The only way to get nether sand is if you walk on soul sand with any boots enchanted with soul speed. After several times walking on it, all souls will be free and the soul sand will be empty, making : nether sand. You can even turn nether sand back to soul sand by killing certain amount of mobs directly on it or in a certain radiance.