You can’t be knocked back if you’re carrying a loadstone.

Blessed loadstones boost your carrying capacity by more than their weight, allowing you to carry more than if you were not carrying the stone at all. The stone would probably still curse itself upon leaving inventory, however.

Loadstones operate more subtly: they increase their weight every time you pick up a new item (one that you haven’t touched yet in the game). At some weight threshold, it autocurses and becomes undroppable.

Carrying a loadstone makes all stone-type missiles (slung ammo, etc) deal double damage - increasing the payload of stones. Also, when blessed or uncursed, it doesn’t weigh as much as cursed.

Dropping a loadstone has a chance of producing the message “You drop the loadstone right on your foot!” and wounding your legs.

A monster carrying a loadstone is slowed to half or 2/3 of its normal speed.

Gold nuggets as a replacement for loadstones. They are expensive, but heavy, and generate cursed. Like loadstones, cannot be dropped when cursed.

You can break and destroy a loadstone in inventory by applying a pickaxe to yourself, or rubbing the pickaxe on the loadstone.

Carried loadstones prevent knockback, including Newton’s Third Law effects. Possibly it prevents levitation entirely.

Applying heat to loadstones demagnetizes them and turns them into flint stones.

Magnet traps that attract metal items out of your inventory, but also attract loadstones and are a means of getting rid of them.