Jon...Jere is the footnote from Peck on these 1868 quarter-farthing through penny copper-nickel strikes..."Usually recorded as nickel. Actually these pieces and the rest of the set down to the quarter-farthing are composed of a copper-nickel alloy. The Mint has no record osf its exact composition, but it is believed to be copper 80: nickel 20, which was the alloy used for the Jamaica penny and halfpenny of 1869. As the latter were the first British coins containing nickel to be used for currency, it is probable that the 1868 sets were trial strikings in connexion with that issue. Pure nickel is magnetic, but ceases to be so when alloyed with more than 30 per cent. of copper. Experiments at the Mint indicated that for coinage purposes, the nickel content of copper-nickel alloys should lie between 20 and 30 per cent. With less than 20 per cent. of nickel the alloy has a yellow tinge, and more than 30 percent, causes bubbles int he castings. (Craig, p.326.)" Insofar as the rarity is concerned, the Penny is listed as Extremely Rare, the halfpenny as Rare, the farthing as Extremely Rare, the third farthing as Very Rare, and the quarter farthing as Very Rare.