This is the first Franklin Half dollar struck at the Denver Mint and also the first year in which Franklin Half Dollars were produced. This year the Mint only struck 4,028,600 coins at the Denver Mint, a slightly higher amount of those struck at the Philadelphia Mint for the same year. For the most part, the 1948-D is considered a low mintage coin for the Franklin Half Dollar series since there are only 10 coins in the series which have a mintage lower than 5 million.
The 1948-D is fairly common in circulated grades all the way up to about MS63 condition that it can be purchased at a premium tied silver melt values. In MS64 condition it tends to be a bit more difficult and doesn't always trade based of silver spot prices. In MS65 it is now less available with possibly no more than ten thousand coins in existence. In MS66 it is scarce where possibly 300-500 examples exist. In MS67 is almost unknown with the exception of one sole example certified MS67 with the FBL designation by PCGS and none being finer.