• Copper always wants to turn the color of an old penny when used inside a home. It does not turn green.
• Lacquered sink interiors will fail at some point, exposing raw copper which will turn the color of an old penny.
  See the penny test
• It takes at least 7 years of exposure to the outdoor elements before copper will begin to turn green. (I am still waiting)
• Untreated copper (with or without a patina) will kill bacteria as aggressive as MRSA and E-Coli in as few as 4 minutes
  (the same germs will live up to 30 days on stainless steel)
• There is a difference between cold rolled copper and annealed copper. We use 14 gauge pure cold rolled copper, which is very hard. Annealed copper is often used when you see hammered sinks coming in from outside the US. If you hear that a company is using 14 gauge copper, they are likely using annealed copper. It is quite soft. The sink in the top video is made of 16 gauge annealed copper. (an import)
• There can be a difference in purity between newly mined copper and recycled copper. Virgin copper is 99.9% pure. The process required to recycle copper to the same purity is very expensive, therefore rarely done. Our copper meets the new California and Vermont regulations regarding NO LEAD in plumbing products. This is a quote from Copper.org with regard to recycled copper: "The only significant drawback to using recycled copper is that it may contain trace impurities that negatively impact its properties." Of the 1,092,600 tons of scrap that was directly remelted in the US in 1996, about 22% was recycled into ingot cast copper alloy products by producers and foundries, 70% was recycled by brass mills and about 8% was reused by other industries, powder-producers, and by wire rod mills.
   

By the way, I may refer to our copper being 16 gauge (our stainless is 16 gauge) in a video or two. It is my old age folks. We use, and have always used 14 gauge for our copper sinks.