WordNet records no synonym and no antonym for mohs scale. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a scale of hardness of solids; talc is 0 and diamond is 10; ordering is determined by which substance can scratch another substance
Synonyms, antonyms and the broader and narrower relations for mohs scale come from Princeton University’s WordNet. Full sources and licences.