Chinese Medal in Velvet-Lined Clam Case — “Gift” and “Minister of Criminal Justice” or “Metropolitan Police Department Detective Chief”

This unique large-sized coin-like medal comes in a velvet-lined clam shell case.

The velvet is purple and is quite worn; the coin itself weighs about 2.5 ounces and seems to be pewter; the case is just over 5.5 inches long.

The back of the coin has some Chinese characters on it. 

Click on photo below to enlarge: