Abstract: A multi anvil device is provided for creating substantially hydrostatic pressure conditions on a cubic sample vessel having a. volume of up to approximately one cubic centimeter. The device comprises a plurality of pressure members disposed within a tubular locking ring. The pressing members collectively define a right cylinder form having a hollow cuboidal center, and the members are formed to cooperatively reduce the volume of the hollow center under compression of the device. Two generally disc-shaped end plates are disposed at the ends of the device to receive and transmit forces from an external source to the pressing members. The pressing members and the locking ring are unconstrained and reactive to misalignment of forces applied to the device and misalignment of the components within the device. A zirconia cubic sample vessel having chamfered edges is also provided for encompassing the sample during operation of the device.