Devi Durga is Goddess of Shakti (Strength, power, energy). Being the deity of the cosmic fort (Durg) she is called “Goddess Durga”. Mother Durga is the embodiment of the divine energy and the creative power. According to the ancient scriptures Mother Durga has nine forms or dimensions. The evolution of Shri Maha Saraswati, Shri Maha Laxmi and Shri Mahakali (the 3 main forms of "Shakti") took place from Shri Brahma, Shri Vishnu and Shri Mahesh respectively. Each of these 3 deities gave rise to 3 more forms and hence in all, these 9 forms together are known as Nav-Durga. Hindu people worship these nine forms of Durga or nine forms of Shakti during nine days of Navratri.
Durga Shailputri (Daughter of Mountain) : "Shail" means mountains, "Putri" means daughter. Parvati, the daughter of the King of the Mountains Himavan, is called 'Shailputri". The first among nine Durgas and 1st night of Navratras is devoted to the puja of Shailputri . Her two hands display a trident and a lotus. Her mount is a bull.
The second Durga Shakti is Brahamcharini. Brahma that is who observes penance(tapa) and good conduct. Here "Brahma" means "Tapa". The idol of this Goddess is very gorgeous.One hand hold a "Kumbha" or water pot, and the other holds a rosary. She personifies love and loyalty. Bhramcharini is the store house of knowledge and wisdom. Rudraksha beads are Her most adored ornaments!
The name of third Shakti is Chandraghanta. There is a half-circular moon in her forehead. She is charmful and bright. She is Golden in color, possesses ten hands and 3 eyes. Eight of her hands display weapons while the remaining two are respectively in the mudras of gestures of boon giving and stopping harm. Chandra + Ghanta, meaning supreme bliss and knowledge, showering peace and serenity, like cool breeze in a moonlit night. This Durga Shakti rides a tiger. She is mainly worshipped in Tamil Nadu.
With the fourth night begins the worship of Kushmanda, possessed of eight arms, holding a weapons and a mala ( rosary), her mount is the tiger and She emanates a solar aura. "Kumbh Bhand" means to see the cosmic dance in the form of Pindi; the knowledge of cosmic intricacies in the human race. The abode of Kushmanda is Bhimaparvat !
Fifth name of Durga is "Skanda Mata". Rising a lion as Her chosen vehicle, She holds Her son skanda on her lap. She displays three eyes and four hands; two hands holds lotuses while the other two hand display defending and granting mudras, respectively. Its said, by the merch of Skandmata, even the fool becomes an ocean of knowledge.
Black (or blue ) skin with bountiful hair and 4 hands, 2 clutching a cleaver and a torch, while the remaining 2 are in the mudras of "giving" and "protecting". Her vehicle is a faithful donkey. The destroyer of darkness and ignorance, Kaalratri is the seventh form of Nav-Durga meaning scourer of darkness; enemy of darkness.
The Eighth Durga is "Maha Gauri." She is as white as a conch, moon and Jasmine. She is of eight years old. With four arms and the fairest complexion of all the Durgas Shaktis, Mahagauri radiates peace and compassion. She is often dressed in a white or green sari. She holds a drum and a trident and is often depiected riding a bull.
Ninth Durga is "Siddhidatri". There are eight Siddhis , they are- Anima, Mahima, Garima, Laghima, Prapti, Prakamya, Iishitva & Vashitva.It is said in "Devipuran" that the Supreme God Shiv got all these Siddhies by worshipping Maha Shakti. With her gratitude the half body of Shiv has became of Goddess and there fore his name "Ardhanarishvar" has became famous.Usually shown ensconced a lotus with four arms, She is the grantor of 26 different wishes to Her Bhaktas.