Starry Obsidian has wonderful white to colored spots and patterns on a black background. The surface of Starry Night Obsidian is a little crackly, but it isn’t that noticable because it takes a good polish. Cuts easily and polishes well with diamond.tiffany stone. Some uneven hardness can be encountered in this material, but tiffany stone generally cuts easily and takes a fine polish with diamond, tin or cerium oxide. Mohs hardness is 5 to 6.