To facilitate further preparation, the sawed specimen is usually embedded (or mounted or encapsulated) in a plastic disc, 25, 32 or 38 mm in diameter. A thermosetting solid resin, activated by heat and compression, e.g. mineral-filled epoxy, is best for most applications. A castable (liquid) resin such as unfilled epoxy, acrylic or polyester may be used for porous refractory ceramics or microelectronic devices.  The castable resins are also available with fluorescent dyes that aid in fluorescence microscopy.  The left and right specimens in Fig. 3 were embedded in mineral-filled epoxy.  The center refractory in Fig. 3 was embedded in castable, transparent acrylic.