Design writer Deyan Sudjic wrote: "There is no doubt that dollars look like money. They are in the first place green - clearly the colour of money. American Express pulled off a really intelligent coup when they facelifted their plastic credit card with a new green design clearly inspired by the dollar bill."
The image was just right for its time: the globe image sandwiched between the company name in curved, solid type, the mixture of straight lines and Ionic curves and the head of a Roman legionary at the centre.
Like almost all cards afterwards - Greenpeace's attempt to create a biodegradable version excepted - it was made of PVC. Magnetic strips at the back were added in 1970. Nowadays, of course, there are tens of thousands of credit card designs available and American Express itself has long since been overtaken by MasterCard and Visa.
A very famous American Express Card was at the centre of a US auction in 2011. In October, memorabilia from John Wayne's personal archives, including his American Express card, were put up for auction in Los Angeles, the US.
Wayne's drivers licence and passport, as well as a collection of cowboy boots, hats and a saddle, were also on sale.