Downloading PhasePlot 1.0.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The software is included in Education Tools.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The following version: 1.0 is the most frequently downloaded one by the program users. This free Mac application was originally designed by Mark S. Ghiorso. This free app is suitable for Mac OS X 10.7 or later. The bundle id for PhasePlot for Mac is com.markghiorso.PhasePlot.
From the developer:
PhasePlot is a computational thermodynamics software package for visualizing equilibrium phase relations in application to the Earth and other silicate planetary bodies. The program determines abundances and compositions of solid and liquid phases based upon several thermodynamic data/model collections.
You may want to check out more software for Mac, such as iRNAi, Gee or Arcade Math Blocks, which might be related to PhasePlot.