SHAFAQNA – Q:What are the characteristics of a proper Hijab? A: There are two conditions for a Hijab to be proper: the first is: cover up. A woman should cover up her whole body except for her face and palms. Though, in accordance to some religious authorities, (the more precautionary measure is to) it is recommended that the face and palms be covered, we personally believe, along with several jurists, that it is permissible to reveal them drawing upon God’s saying:” they should not display their beauty and ornaments except what must ordinarily appear,” thus, a woman must cover up her whole body by a nontransparent garment. The second condition is to avoid wanton displays: “and make not a dazzling display, like that of the former Times of Ignorance” It is not permissible for a veiled woman to go out in public displaying her makeup and accessories, or even her body features by wearing a garment that accentuates her feminine features, and thus, emphasize her sexuality rather than her humanity.
Source : Bayynat