Commas- To separate adjectives whose order could be reversed

The order of certain adjectives can be interchanged in a sentence with a comma in between e.g. “hot, dry desert” or “dry, hot desert”.
If the order of adjectives cannot be switched, a comma cannot be used e.g. “Australia is home to some of largest coral reefs in the world”, because “Australia is home to some of the coral largest reefs in the world” is incorrect.