Mathematical Monospace Capital J
HTML Entity Browser Test:

U+1D679 is the Unicode hex value of the character Mathematical Monospace Capital J, which is categorized as "uppercase letter" in the Unicode 6.0 character table.

In addition, U+1D679 is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+1D679
General Category Uppercase Letter [Code: Lu]
Canonical Combining Class 0
Bidirectional Category L
Decomposition Mapping <font> 004A
Mirrored N
Unicode Character Encodings
Mathematical Monospace Capital J HTML Entity &#120441; (decimal entity), &#x1D679; (hex entity)
Windows Key Code Alt 120441 or Alt +1D6791
Programming Source Code Encodings Python hex: u"\u1D679", Hex for C++ and Java: "\u1D679"
UTF-8 Hexadecimal Encoding 0xF09D99B9
1 To type a Unicode symbol in Windows, hold down the ALT key and enter the decimal or hexadecimal code provided using the numeric keypad. The decimal alt code (Alt 120441) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +1D679) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Mathematical Monospace Capital J character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.