Ron Guth:
1819 Half Eagles are represented by two distinct die varieties: 1819 (Close Date, Normal Reverse) and 1819 5D/50. Both varieties are rare, but the Close Date is definitely the rarer of the two (none have appeared at auction in the past decade). The 5D/50 variety includes five to six Mint State examples, the finest of which isa single PCGS MS65.
The rarity of 1819 Half Eagles resulted from the destruction of large quantities of early U.S. gold coins whenever their gold value exceeded their face value in the 1800s. Were it not for coin collectors, the destruction would have been more widespread.