Aluminum Silicate System: Experimental Determination of the Triple Point

The kyanite-sillimanite-andalusite triple point exists in the pressure-temperature plane at 8 +/- 0.5 kb and 300 +/- 50 degrees C. Reactions are accomplished experimentally with a Bridgman opposed-anvil press (with an external furnace), modified to provide shearing of the sample charges. All three equilibrium boundaries are proved by reversed reactions.