Below the stone ring of a nineteenth-century Navajo hogan: a piece of sun-purpled glass—pre-1914, when a process was discovered that prevented clear glass from purpling in sunlight—between two snake vertebrae.
Perhaps you’d like to write that one?
There’s a Story Here
WORLD-BUILDING and WILDERNESS: 
They stopped adding manganese to the glass. It was added to counteract the greenish tinge (from Iron? I’m guessing). That’s what the sun transforms and turns purple. I developed a beautiful pale purple glass back in the day with tin and manganese and nickel—at least that’s what I recall. It’s been almost 60 years.