Hmmm, AMEX should really work on their card design. Usually I do not care how CCs look like but in the last 2 weeks I was told like 4 times at the lounge front desk (3 contract lounges, on LX lounge): "Oh, no you don't have access - this is a silver card."

In the end the "Star Alliance Gold" print and taking a closer look at the card they could saw the "silver stripe" is actually a "diamond stripe" and let me in. But it is really uncomfortable have to explain yourself at the lounge front desk.