Abstract: To understand our origins, we must understand the role that interstellar dust plays in delivering heavy elements to planetary systems. This requires an understanding of the chemical composition, sizes and shapes of interstellar dust: astromineralogy. X-ray observations provide the most direct means for astromineralogy through the absorption signatures of dust imprinted in the spectra of bright Galactic X-ray sources. I’ll review the latest results in astromineralogy and our work on connecting interstellar dust with suspected extra-solar grains collected in our own Solar System. I’ll also describe how the recently launched XRISM space mission is poised for major breakthroughs in astromineralogy. Finally, I’ll show how I am adapting this work to study aerosols in exoplanet atmospheres, which have the power to alter planetary climate and habitability. By investigating exoplanet transits at short wavelengths, we are opening new windows on aerosols, atmospheric escape, and the role that stars play in sculpting planets.