REFRACTORY DUST IS AMONG THE BUILDING BLOCKS OF OUR SOLAR SYSTEM. ITS MICROSTRUCTURE ATOMIC STRUCTURE AND CHEMICAL COMPOSITION CONTAIN CLUES TO THE DUST-CONDENSATION CONDITIONS OF OUR SOLAR NEBULA AND ANCIENT CIRCUMSTELLAR ENVIRONMENTS. HERE WE PROPOSE MEASUREMENTS FROM THE MICROMETER SCALE TO THE ATOMIC LEVEL SUPPORTED BY A COMPUTATIONAL EFFORT AIMED AT UNDERSTANDING THE ORIGINS AND THERMODYNAMIC ENVIRONMENTS OF THE FIRST NEBULAR SOLIDS AND ANCIENT CIRCUMSTELLAR DUST. OUR PROPOSED WORK BUILDS ON ADVANCES AND PRODUCTIVITY FROM OUR PREVIOUS EFFORT AND IS CRAFTED AROUND OUR NEW CAPABILITIES IN STATE-OF-THE-ART MICROSCOPY AND COMPUTATIONAL MATERIALS SCIENCE. OUR PROPOSED EFFORT IS DIVIDED INTO THREE DISTINCT BUT RELATED TASKS THAT EXAMINE METEORITIC COMPONENTS WHICH DEVIATE FROM ESTABLISHED EQUILIBRIUM THERMODYNAMIC PREDICTIONS. CALCIUM-ALUMINUM-RICH INCLUSIONS (CAIS) IN METEORITES ARE THE OLDEST SOLAR SYSTEM SOLIDS AND ARE BELIEVED TO HAVE FORMED WITHIN THE INNER SOLAR PROTOPLANETARY DISK. WE HAVE IDENTIFIED MINERAL ASSEMBLAGES WITHIN CAIS THAT ARE NOT CONSISTENT WITH LONG-STANDING EQUILIBRIUM THERMODYNAMIC PREDICTIONS. IN TASK 1 WE PROPOSE DETAILED STUDY OF THESE ASSEMBLAGES AT SCALES RANGING FROM THE MICROMETER TO THE ATOMIC TO UNDERSTAND THEIR THERMODYNAMIC ORIGINS. CIRCUMSTELLAR (PRESOLAR) GRAINS WERE DISCOVERED IN METEORITES JUST OVER 30 YEARS AGO AND SINCE THEN MANY TYPES OF GRAINS HAVE BEEN IDENTIFIED. THEIR STRUCTURES AND COMPOSITIONS HOLD IMPORTANT CLUES TO THE NUCLEOSYNTHETIC AND THERMODYNAMIC PROCESSES THAT OCCURRED IN AND AROUND THEIR PARENT STARS. IN TASK 2 WE PROPOSE TO EXAMINE THE ORIGINS AND CONDENSATION CONDITIONS OF GRAINS THAT APPEAR TO DEVIATE FROM ESTABLISHED THERMODYNAMIC PREDICTIONS PARTICULARLY SIO2 GRAINS FE-RICH SILICATES AND FE-BEARING OXIDES. WE WILL PROBE SUCH MATERIALS DOWN TO THE ATOMIC LEVEL TO DETERMINE WHETHER CONDENSATION OCCURRED VIA EQUILIBRIUM PROCESSES IN CIRCUMSTELLAR ENVELOPES. IN TASK 3 WE PROPOSE TO PERFORM THERMODYNAMIC MODELING INFORMED BY QUANTUM-CHEMICAL CALCULATIONS TO DETERMINE THERMODYNAMIC PARAMETERS FOR SOLID SOLUTIONS RELEVANT TO IDENTIFIED CAI AND PRESOLAR-GRAIN PHASES. MICROSTRUCTURES THAT ARE INCONSISTENT WITH ESTABLISHED PREDICTIONS WHETHER FOR THE EARLY SOLAR NEBULA (TASK 1) OR CIRCUMSTELLAR ENVIRONMENTS (TASK 2) RAISE FUNDAMENTAL QUESTIONS AS TO WHETHER AVAILABLE THERMODYNAMIC DESCRIPTIONS ARE INCOMPLETE THE PRESUMPTION OF EQUILIBRIUM IS WRONG OR SOME COMBINATION OF THE TWO. WE WILL USE THE RESULTS OF THESE CALCULATIONS TO DETERMINE THE CONDITIONS UNDER WHICH SUCH MATERIALS CONDENSED AND HENCE THE PRESSURE-TEMPERATURE CONDITIONS I.E. THERMODYNAMIC LANDSCAPES OF THE INNER SOLAR PROTOPLANETARY DISK AND CIRCUMSTELLAR ENVIRONMENTS. WE WILL PLACE THESE RESULTS INTO THE CONTEXT OF DYNAMICAL MODELS OF THE TRANSPORT AND EVOLUTION OF PROTOPLANETARY AND CIRCUMSTELLAR DUST.