The Double-Struck Capital Gamma symbol (ℾ). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Letterlike Symbols.
The quickest way is to copy ℾ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
ℾ is U+213E (decimal 8510).
Use ℾ in HTML to render ℾ on a web page.
On Windows you can type it with Alt+8510 (hold Alt and enter the number on the numeric keypad).
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