It is possible to get more than Stone when mining Soil.

When a soil voxel is mined:

Drop one of:

3% of chance to drop up to 20 Champignons

5% of chance to drop up to 20 Shiitake

1% of chance to drop up to 2 Amanita Muscaria (Alien soil only)

2% of chance to drop up to 1 Beetroot

2% of chance to drop up to 1 Carrot

3% of chance to drop up to 20 Arnica

3% of chance to drop up to 10 Chamomile

5% of chance to drop up to 5 Aloe Vera

3% of chance to drop up to 10 Mint