Abstract: The compositional make-up of interstellar dust and the relative abundances of chemical elements in astrophysical environments are not well understood, despite good progress. Since dust is a primary repository of the interstellar medium, and is responsible for the chemical evolution of stars, planets, and life itself, it has a profound effect on many areas of astrophysical research from cosmology to star and planet formation. High spectral resolution X-ray instruments on powerful X-ray satellites (e.g. Chandra, XMM-Newton, Suzaku) pointed through dust and gas at bright black hole and neutron star systems can be used to study dust and intervening material in unique ways. With the new subfield of High Energy Condensed Matter Astrophysics as its goal, I will discuss a new technique for determining dust composition and depletion using X-rays, initial progress, and future prospects.<br>