All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Black colour is not a sacred colour in Islamic legislation, and it is not forbidden for a woman to wear a specific colour. She can wear any clothes that cover her 'Awrah (Parts of the body that must be covered in Islam for a woman). However, these clothes should meet the religious requirements of women's dress whatever their colour is, provided that this colour is not an adornment in itself, if it is the outer garment of the woman, and is not an imitation of men or non-Muslim women. Imaam Al-Bukhari reported that 'Aa'ishah "did not see any harm for a woman in a state of Ihraam when performing Hajj to wear jewellery or black clothes." Also, a woman can wear new clothes in Muharram or any other month. It is not correct to believe that a woman cannot wear new clothes in the month of Muharram. Such statement is misguidance and has no evidence from the Book of Allaah and the Sunnah of the Prophet . Rather, this is closer to the form of omen that the Prophet warned us against as he said: "An ill omen is a form of Shirk, an ill omen is a form of Shirk, an ill omen is a form of Shirk." [Abu Daawood].
Allaah knows best.