Apart from regular circulating coins, in 1969 a pair of commemorative silver coins were also issued: a crown (equal to five shillings) and a pound.
According to "Stephen Album Rare Coins", a company which has sold a handful of the rare crowns:
"Little is known about this seldom encountered commemorative, probably intended for two years of independence. ... No specimen has appeared at auction or for sale in recent years, to the best of our recollection."
The cataloger for Album suggests that the piece is often attributed to an Italian firm known as Istituto Numismatico Europeo, "but there is no evidence to confirm this assumption".
Composition: 0.750 silver (0.6173 oz. ASW). | 
Search for Biafra: Pound 1969 (Silver) on eBay 