Do I have to show my employer my social security card if I've shown a pic ID & Native tribal doc with my SSN?

I filled out an I-9 at my new job and showed my state picture ID and Document from my tribe that gives my SSN. That was fine. The employer then asked that I show my original Social Security Card to their HR office within 10 days or I would be taken out of their payroll system. Is this legal? Or are they discriminating against me?

They are a little confused. The entire purpose of requiring you to show your Social Security card is to prove that you are a legal citizen or resident of the United States. Your tribal documentation proves that you are not only a legal citizen of the United States, but one of the few people who can claim being native to the United States.
If this was ever challenged in court, you would win, but why go to that trouble if you don't have to? Just humor them.

Your employer is required by federal law to make a copy of your SS card and drivers license and keep it on file. If he doesn't, and they are audited by the government, they can be fined. On most job applications, there is a part the employer (usually HR) signs that states the person has physically seen the ID's produced. The copy goes in your employee file.

damn indians causing more trouble.

Ahhh, just show them. Less trouble. They just probably never saw that form before. They just want to stay legit.