MySQL’s utf8 permits only the unicode characters that can be represented with 3 bytes in UTF-8. Here you have a character that needs 4 bytes: \xF0\x90\x8D\x83 (U+10343 GOTHIC LETTER SAUIL).
If you have MySQL 5.5 or later you can change the column encoding from utf8 to utf8mb4. This encoding allows storage of characters that occupy 4 bytes in UTF-8.
