Tazart, I have no doubt that the center teardrop is Amazonite as you describe. I would also venture to say that the square stone directly to the left (and perhaps the rectangle to the right) is from the same stone, maybe even the same mine.

The date on the piece is 1820. It is signed by the artisan "G.R"

Still unsure about the scarab and the teardrop to the far left, that looks like raw turquoise, the one on the right could be jade?

This has become an endlessly fascinating and frustrating puzzle!