COIN AND TICKET 

The dollar  is the monetary unit of the Hong Kong Special Administrative Region. It is divided into 100 cents and its ISO 4217 code is HKD. Normally abbreviated with the symbol of the dollar ($), but to differentiate them from other currencies with the same denomination HKD is used. The Hong Kong dollar is the ninth most traded currency in the world.

COIN
In 1863, the first coins of 1 thousand, 1 and 10 cents were introduced, followed in 1866 by the denominations of 5 and 20 cents and ½ and 1 dollar. The coins of 1 thousand and 1 cent were minted in bronze, and the other denominations in silver. In 1866 the manufacture of 1 thousand coins ended, while those of ½ and 1 dollar ceased in 1868. The only coin that was made again was the ½ dollar in 1890, with the denomination of 50 cents. In 1905 the silver was substituted for the minting of coins, except the one of 5 cents during a brief period of time between 1932 and 1933.
TICKET
Today, the issuance of banknotes denominated in Hong Kong dollars is the responsibility of the Hong Kong Monetary Authority. Under your license, only three private banks can issue tickets for circulation in the administrative region. The Monetary Authority itself also issues its tickets. Normally in the other countries the only one competent to issue money is a single central bank, however the case of Hong Kong is not unique, as for example in Macao or in the United Kingdom.