Shyamantak is a rare Indian name which is sounds similar to the word Syamantaka. Syamantaka, Syamantaka mani or the Syamantaka Jewel, is perhaps the most famous jewel in Hindu scripture,
supposed to be blessed with magical powers.
Alternatively it could also refer to God Krishna, (the eighth
incarnation (avatar, or avatara) of the Hindu god Vishnu), as Shyam(meaning dark,
black and blue) is another name for Krishna.