Mariamman and Kaliamman Temples in Tamil Nadu, India
Māri or Mariamman ("Mother Mari"), or simply Amman ("mother") is the South Indian Hindu goddess of disease and rain. She is the main South Indian mother goddess, predominant in the rural areas of Tamil Nadu, Karnataka and Andhra Pradesh. Māri is also closely associated with the Hindu goddesses Parvati and Kali. Māri originated as an ancient village goddess related to fertility and rain. And she was the smallpox goddess before this disease was eradicated. Now she cures all so-called heat-based diseases like rashes and chickenpox. People also pray to Mariamman for progeny, a good spouse, etc. Most Mariamman temples are humble shrines in villages, where non-Brahmins act as priests. In many rural shrines, the goddess has no form and is represented by a granite stone with a sharp tip, like a spear head. This stone is often adorned with garlands made of limes and with red flowers. These shrines often have an anthill that can be the resting place of a cobra. Milk and eggs are offered to propitiate the snake (compare my gallery: Naga Cult - Snake Worship - in Tamil Nadu, India https://pbase.com/neuenhofer/naga_cult_in_tamil_nadu ).
Have a full preview of my book about Dravidian deities (120 pages with lots of photos) in German: AYYANAR UND MARIAMMAN, DRAVIDISCHE SCHUTZGÖTTER IN SÜDINDIEN
and in English: Christa Neuenhofer, AYYANAR AND MARIAMMAN, FOLK DEITIES IN SOUTH INDIA (see below).