The historical Elder Futhark consists of 24 runes, so the unmarked stone is not an additional historical rune. Blank stones are used in some modern divination systems, where customers may assign them meanings such as the unknown or fate; those following a strictly historical 24-rune system can simply leave it aside.

No. Runes were originally characters in Germanic writing systems, while the detailed meanings and layouts used in modern rune readings vary between traditions and authors. Retailers should therefore avoid suggesting that there is one universally correct interpretation for every symbol.

They can, but a cloth, mat or other slightly cushioned surface is preferable. Repeatedly casting gemstone pieces onto hard surfaces can cause scratches, edge chips or damage to both the stones and the furniture underneath.