The World Federation One Stop Fiqh

Ruling 2578

If a person usurps a non-fungible item and it is destroyed, in the event that it acquired a quality that increased its value while it was with the usurper – for example, [it was an animal and] it gained weight before it was destroyed, he must pay the amount it was worth when it had gained weight. This applies as long as the gain in weight was not a result of him better tending to it. If it was a result of him better tending to it, then it is not necessary for him to pay the increase in value.