The Praying Mantis™ is a highly efficient diffuse collection system that minimizes the detection of the specular component. The module permits easy and reliable diffuse reflection analysis of solids and powders by FT-IR and UV-VIS spectroscopy and analysis of catalysts and other powders in a temperature and/or pressure-controlled environment. Ellipsoids pivot to provide easy access to the sampling area and incorporates to 6:1, 90° off-axis ellipsoids which form a highly efficient diffuse reflection illumination and collection system. This unique configuration deflects the specular reflectance away from the collecting ellipsoid, minimizing the associated spectral distortions. The Praying Mantis™ also can be configured to study materials and reactions in controlled environments with the appropriate diffuse reflectance reaction