According to A.Mc., apparently these things only started to appear c. 1710 - 30, and they were used to cool wine, beer and cider, as well as champagne - so Christine may well be correct that this is intended for white wine - they are sometimes referred to as 'double decanters'. This one is no doubt very modern - sometimes the ice pocket is sealed with a metal lidded cork bung, and there are examples known without glass stoppers to the neck of the decanter - similar to a carafe.
All information courtesy of Andy McConnell's wonderful book.