Mathematical Double-Struck Capital X
🔲
This character has not been recommended for emoji presentation by Unicode. It will therefore display as a a single black-and-white Unicode character across most platforms.
A blackboard bold version of the letter X, which according to some sources is occasionally used to denote an arbitrary metric space within mathematics.
The logomark for the social media platform X (formerly Twitter) appears identical to this character.
Mathematical Double-Struck Capital Xa été approuvé dans le cadre de Unicode 3.1 en 2001.