Just last night, I was flipping through a book received as a holiday gift. In it was an image of the famous Tut death mask. Supposedly the dark blue stripes in his menes headdress are not made of precious stone as previously thought, but of a special type of glass. There were no details as to where the glass originated. I don't know if this relates to your question, but it sparked debate in my household.

I recalled hearing elsewhere- possibly on the news, that the glass could not be locally or universally placed. In other words, no one could determine where it came from, nor what process was used to create it, but it was unique in all the world and not from Egypt. My significant other disagreed, insisting the glass was made at the world's most ancient glass making site in Egypt.