Starlight Minotaur. The minotaurs I depict are different from the Auroch Gohma. I have three different kinds of minotaur goma, fire, storm and starlight. The fire ones can breathe fire and withstand extreme temparatures, the storm ones breathe out storms and raise winds and lightning, and the starlight ones can summon light in dark places, and bring forth darkness is bright places.
The meditation stone is a sort of agatized magic/psychic substrate. It would cast those rainbows even without the cup of stars that the minotaur is holding.