Nature of mother siddhidatri
Lord Shiva had attained all those siddhis by worshiping Mother Shakti. With his gratitude, half the body of Lord Shiva became of mother power and hence he came to be called Ardhanarishwar.
Mother form
This incarnation of Maa Durga dispels ignorance and imparts knowledge to her devotees. She is also worshiped by Devas, Gandharvas, Asuras, Yakshas and Siddhas. Mother sits on a lotus and rides a lion. She has four hands and a mace in the right hand, a circle in the upper right hand, a lotus flower in the left hand and a conch in the upper left hand.
Her glory and power are infinite and worship the mother Siddhidatri on the last day (ninth day) of Navratri and mata gives all the siddhis to her devotees and also signifies the successful completion of Navratri festival.
मंत्र (Mantra)
ॐ देवी सिद्धिदात्र्यै नमः॥
Om Devi Siddhidatryai Namah॥
सिद्धगधर्व यक्षाद्यैरसुरैरमरैरपि।(Siddha Gandharva Yakshadyairasurairamarairapi।)
सेव्यमाना सदा भूयात सिद्धिदा सिद्धिदायिनी।।( Sevyamana Sada Bhuyat Siddhida Siddhidayini॥)