“A Heart of Opal Fire” is Mariah Garnett’s debut solo show at Commonwealth and Council, open through August 7. In this new body of work, Garnett has combined meditations on spirituality, mental health, and art making, simultaneously acknowledging her family’s complicity in structures of colonialism and cultural appropriation. The great-grandniece of the concert pianist Ruth Deyo, who wrote an opera called A Diadem of Stars in the 1920s, based on her relationship with an Egyptian stone bust called TAA, Garnett has taken it upon herself to enact parts of Ruth’s composition, which never came to fruition. At the center of the show, The Pow’r Of Life Is Love examine’s Ruth’s Egyptomania in the first-ever public presentation of this musical work, which are executed through Garnett’s queer gaze.