Add a upgrade for silver chest to diamond chest. This is the only chest upgrade without an equivalent item.

basically, you save 4 gold and 1 step if you break the chest to upgrade it

This is possible correct? There is an upgrade from sliver chests to gold chests, and from there you can upgrade to diamond.

yes, but there is a crafting recipe where silver chest + 5 glass + 3 diamonds = diamond chest. This is the only chest upgrade recipe without it's in world counterpart