Thank you all for sharing your knowledge.
After reading your posts, and discussing with some local plumbers, appliance specialists, and water company, I am confident with knowing that the stuff is copper sluff. I will replace the copper tube with potable plastic tubing.
One more thing I would like to run by you all.
After thoroughly thawing, drying, and cleaning the entire Fridge/Freezer unit, and reassembling I am back to my original problem, (which I hadn't detailed above): the water continuously flows from the ice maker. In other words, after reassembling I plugged the fridge/freezer back into power and the water supply continues to flow into, and then overflow out of the ice maker.
Because [A] the water supply pressure is strong, [B] the continuity of the (newly replaced) water inlet valve is good, I assume I simply have a bad ice maker. Do you folks agree?
How does the water inlet valve know when the ice maker is full of water, and to close the valve?
Does anyone know where I can acquire an Ice Maker cheaper than $112, for Amana SRD20S4W?
I did find a replacement ice maker for $35 but Im waiting to hear back from them. The price makes me a little suspect when compared to other prices I have seen. Thank you all for sharing your knowledge. http://www.seneca-river-trading.com/reicbforwhse.html