In early chemistry “Mysterium” was what alchemists called any of various unknown elements thought to make up existing forms of matter. This old definition seems perfect for defining the special, enigmatic relationship we have with art. Mysterium is also, fittingly, Modern Art Midtown’s newest exhibit. The show focuses on abstraction and features six artists whose work and process gives a nod to unpredictability, texture and consciousness. John Andrews’ graphic circular paintings layer wax and pigment in thin layers to reveal intricacies beneath their surfaces. Janet Eskridge uses combinations of encaustic, paper, objects and stitching for her assemblages that serve as containers for memory. Justin Meyers balances simple subject matter with an eccentric approach, utilizing graphite and charcoal to connect more immediately with viewers. Medium becomes the focus in Steve Mueller’s works that combine mined pigments, paper, and reactive process to establish unique, unexpected compositions. Michael Tegland showcases the intimacy of his process with meticulous markings in graphite, connecting the viewer to the artist’s hand. Graceann Warn’s layered surfaces in encaustic, oils and paper reflect her abstractions inspired by archaeology.