Not all platinum gets that patina. The most common plat alloy is 95plat/5cobalt. It's the cobalt that makes the Pt more susceptible to the patina, though it's easily polished. Other plat alloys that are not as susceptible to the patina include irridium, ruthenium, and Plat-S. Plat-S is a patented (I believe) alloy and the exact mix I don't think is public knowledge. My ER is made of plat/Ru mix. My WR was custom made of Plat-S. I cannot tell the difference between the two metals, and they are both VERY shiny and haven't had the patina. That being said, I've only had the ER for 21mos, and the WR for about 10. I mostly wear my plain WG band anyway.......Platinum is heavier, and gets that patina I am not at all crazy about.
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