allows for each of the 6 anvils to make contact with each face of the sample assembly. The outer portion of the sample assembly is the pressure medium, which is commonly either boron epoxy (BE) or mullite. The choice of pressure medium used in the sample assembly depends on the ultimate goal of the experiment. Boron epoxy is a self gasketing material in the D-DIA, which means it can produce a seal between all the anvils during deformation, but it has been shown to impart a significant amount of water to the sample during the experiment. This added water to the sample makes it impossible to conduct rheology experiments under anhydrous conditions. The other pressure medium material, mullite, leaves the sample very dry, but does not have the ability to self-gasket in the D-DIA. For this reason, when mullite is used as a pressure medium it needs to be used in combination with a gasket material. Typically the gasket material used is pyrophyllite, and the mullite will be machined into a sphere which sits in pyrophyllite “seats”, forming a cube. In the sample assembly, inboard of the pressure medium and surrounding the sample is an internal resistive heater. The heater is a sleeve which the cylindrical sample fits into, and typically is made of graphite, or can also be made of different types of metal. In deformation experiments pistons are needed on either side of the sample. Alumina is commonly used as it is harder than most sample materials, allowing deformation of the sample. Another design element that can be included into the sample assembly is a thermocouple. Thermocouples can be placed either as side entry (one that enters the center of the cube from and edge) or can be a top entry thermocouple (one that enters the top face). In the case of the top entry thermocouple, it can be simultaneously be used as the top piston, but the temperature is being read far from the sample center. The side entry thermocouple reads the temperature closer to the sample center, but the placement usually involves a hole to be drilled in the middle of the furnace, altering the heating characteristics of the furnace. To avoid both downside associated with wither thermocouple some sample assemblies do not use a thermocouple; temperature is instead either calibrated from the relationship of watts vs. temperature or calculated using the known pressure and calculated