Thanks to a terrific web site by Bob Reis of Raliegh, NC, you probably have a Yin and Yang Chinese Amulet or charm, produced to look like an old Chinese cash coin. The designation for this dragon and phoenix piece is Zhou Yuan Tong Bao.
Bob's piece pictured sold for about $100 US dollars. It is in good shape and is an original amulet. Yours may be the real thing, or a modern reproduction like the one in our secondary picture (from Mystic Awakening), worth a few US dollars.
CoinQuest thanks Bob Reis for the use of his image. It certainly is an interesting coin.
According to SmilingBamboo.com,
'The imperial dragon and the royal phoenix are one of the most important celestial animals in Feng Shui. They are known as the perfect harmonious combination of yin (phoenix) and yang (dragon). The dragon phoenix coin invites love, marital happiness and passion. It is also the perfect item for the bachelor or bachelorette. The dragon/phoenix combination is frequently found in restaurants, bedrooms of the newly wed, and anywhere there is a unity or joint venture of two parties.'
You can see a similar coin with two dragons (no phoenix) at this link. A modern dragon/phoenix coin appears here.