Vintage Hieroglyph Design Brooch Deer Marked 800 Silver Gold Vermeil Plated?

Vintage Brooch Antelope Hieroglyph Design Marked 800 Silver w/ Gold Vermeil Plated? I have only found two other brooches like this, and one is marked as 800 silver and the other is marked as vermeil gold. I honestly don't know because an 800 mark typically means 80% pure silver, but this is a gold tone. This could mean it is silver, plated with vermeil gold. An 18K gold acid does turn it a little milky blue, and the scratches hold up to the acid. Unfortunately, I think my silver acid is bad. Another mark looks like "551" or "557" but it is partially worn away. The last mark is difficult to decipher. This received a cleaning with a soft brush in fine jewelry cleaner. There is a slight bend to the pin, but it still hooks and holds. It looks to have a bit of verdigris on the back. Please review the pictures well and carefully. Please see the pictures for more details and the full item condition. Thank you.