Irans LB Perfect Peach Onyx can be used for exterior applications in cold climates. However, it is important to consider the properties of this specific stone before making a decision. Onyx is a type of calcite mineral, which is relatively soft and can be prone to weathering or damage in extreme temperature variations. Therefore, it is recommended to consult with a professional stone contractor or supplier who can provide guidance on the suitability and maintenance requirements for using Perfect Peach Onyx in cold climate exterior applications.