Credit card chip contacts

I've seen credit cards with yellow contacts and with dull silver contacts. Does anybody know what is the material used for these two varieties?

TIA

Gold and silver ?

...R

Thanks for the reply. I thought of those two but it seems an expensive option for a credit card.

dougp:
Thanks for the reply. I thought of those two but it seems an expensive option for a credit card.

There won't be very much of it. I'd guess you would need to recycle a large number of cards to get $100 worth of gold.

...R

Robin2:
There won't be very much of it. I'd guess you would need to recycle a large number of cards to get $100 worth of gold.

...R

Yes, if it's a precious metal the thickness is probably measured in 10/1000ths of an inch.

I believe the unit of measure for such things is µin (microinch).

dougp:
Yes, if it's a precious metal the thickness is probably measured in 10/1000ths of an inch.

10/1000 = 1/100. If the gold was that thick my card would be worth more than the amount in my account.

I suspect microns is the more likely unit of measurement. Or the even smaller micro-inch that @Coding Badly mentioned. I never heard of micro-inch before - but that may be just because I am on the right side of the Atlantic.

...R

Robin2:
Or the even smaller micro-inch that @Coding Badly mentioned.

After a spot check a Digi-Key: That does seem to be a common unit for gold alloy contact coatings. 50 to 200 seems to be a common range.

A micro-inch is 0.0254 microns so 50 µin would be 1.27 microns.

...R

Robin2:
10/1000 = 1/100.

I misstated. My intent was .0001 inch. Apparently even that's much more than needed.

[quote author=Coding Badly date=1526629450 link=msg=3736855]
After a spot check a Digi-Key:[/quote]

Wish I'd thought of that. I put 'credit card metal' and a few variations in the search bar and got lots of off-target results.

But, I did learn that there are metal credit cards. Who knew?

dougp:
I misstated.

I had figured that. I was just having fun.

...R