A frame for optics used in interferometers that may include different materials having substantially similar, identical, or as close as practicable coefficients of thermal expansion from the material(s) used to make the beamsplitter and/or compensator without warping, bending, tilting or distorting the optics. The beamsplitter and/or compensator are mounted onto the frame of the interferometer using a three-point method of mounting, preferably using three pins for each component. Preferably, the pins are made of the same material as the beamsplitter and compensator, and all three components are made of Potassium Bromide (“KBr”) or Calcium Fluoride (“CaF2”) such that the optic instrument can operate to scan into the mid or far infrared. Stability in optical alignment is therefore achieved without requiring the optic instrument include only one material. The invention provides stability in situations where it is not possible to utilize a single material for every component of the interferometer.