This is a unique 1837M Monaco 5 Franc die trial pattern struck in copper. The obverse is uniface since only the reverse die was used. It is the regular adopted design of the silver crown struck in silver for circulation.
The silver crown weighs 25 grams and is .900 fine silver. These were struck at the Toulouse Mint and are a one year type. The obverse depicts a large portrait of Honore V facing left. The reverse depicts crowned arms, 2 figures, denomination and date. The issued silver crown (5 Franc) is the ONLY crown issued by Monaco during the 19th century and is extremely rare. A mint state crown is worth several thousand dollars. Recently in a Heritage Auction, the finest known MS 64 in an authenticated and certified NGC holder sold for almost $10,000.
This unique copper die trial pattern is not listed in Krause and is unrecorded in other references as well. In addition to being a uniface copper striking of the adopted design of the silver 5 Franc, it was also DOUBLE STRICK IN THE COLLAR. Evidence from both strikes are clearly visible everywhere.
This is a fascinating and rare combination of a copper off-metal die trial pattern and a mint error, of an extremely rare and expensive crown issued in silver.