The 1st resources utilised were being wood and terracotta, but architects step by step moved on to brick and stone, Specially sandstone, granite, schist, and marble. No mortar was used in the more mature temples and so specific cutting of dressed stones was necessary. Apparently the reactions towards "untouchables" is https://pressnewsfactor.blogspot.com/2024/01/exploring-hanuman-temples-cultural.html