The adornment that is permissible for a woman to display before her mahrams

What is the criterion for the adornment that a woman is permitted to display before mahrams other than her husband?

Allah, Mighty and Majestic, says: [An-Nur:31] The adornment that is normally visible,For example: the abayas, the jilbabs, and the suit clothes; this is the adornment that is visible. As for the adornment that is for beautification, this is not displayed except to mahrams only,On the condition: so that we are safe from fitnah (trial, discord or temptation). If fitnah is feared, even among mahrams, it is forbidden for her to display herself, even in beautiful clothes; because some mahrams may have a distant relationship with this woman, such as a brother through breastfeeding, for example, who does not see her more than once a year, or perhaps once in two years. She may be a beautiful girl, and he may be weak in faith and weak in resolve, so fitnah is feared from him,So we say to these: this is not like a brother through blood relation who is always with the woman.