Am I entitled to claim compensation for the marble that broke while entrusted to the workshop owner, knowing that he was trustworthy with it?

The resolution of disputes takes place in Sharia (definition) courts or by those who act on their behalf, due to their ability to hear all parties and comprehend claims and evidence. As for the Mufti (definition), he hears only from one party and cannot issue an accurate judgment in such cases.

In general, a shared employee (like a factory owner) is liable if the damage is caused by his action, regardless of whether he was aggressive or not, and regardless of whether he exceeded the usual limits or not. However, if the damage occurred due to a cause not attributable to his action, he is not liable unless there was aggression or negligence on his part.