Beryllium (Be) is a lightweight metal with exceptional stiffness and thermal stability, making it a material of interest for a range of high-performance applications. In the field of optics, beryllium is often used for the fabrication of mirrors, particularly for X-ray and infrared applications where its low atomic number and high thermal conductivity are advantageous. Its low density also makes it desirable for aerospace and satellite applications where weight is a critical factor. Despite these advantages, beryllium is challenging to work with due to its toxicity, and it requires special safety precautions during fabrication and handling. Additionally, the material is prone to oxidation, which can be mitigated through coatings or by operating in controlled environments. Although it is not traditionally used in bulk optics due to its metallic nature and the associated high absorption, its unique combination of low density, high stiffness, and thermal stability make beryllium an important material for specialized optical applications.