Code point
U+29F1
Glyph appearance depends on your fonts.
U+29F1
SmU+29F1 ERROR-BARRED BLACK DIAMOND is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Miscellaneous Mathematical Symbols-B block.
Choose the representation you need, then copy its value.
U+29F1
10737
⧱
⧱
E2 A7 B1
29F1
000029F1
%E2%A7%B1
\u29F1
\u29F1
\u29F1
\29F1