Earrings marked GENUINE MARCASITE FINE SILVER PLATED new on card Thailand made

Earrings marked GENUINE MARCASITE FINE SILVER PLATED New on card Not sure of the authenticity of the turquoise, so I included an extreme close up. I can make out "TH" on the backstamp, but I can't read the other part. MC? They do not stick to a magnet. The pictures are part of my description. Please look carefully at the photos and ask questions as needed. Thanks!