Bag of Rune Stones

This bag has 3d6 giant rune stones that are rough the size of a goliath's fist. Randomly picking one of the stones, roll 1d6 and consult the table below. A stone thrown will always deal 2 damage of it's random type and always hits it's target within 60ft. After being thrown, it vanishes.

If you know how to make the runes,  it takes an hour and one 1st level spell slot to make 2d4 rune stones. If you made them, you can reroll the random damage type.

1-Fire

2-Cold

3-Lightning

4-Poison

5-Force

6-Radiant