Late Victorian Early 20th Century 8K Opal Hinged Butterfly Brooch

c1890 Rare piece-I've never seen this type of brooch in 30 years. The piece test as low karat gold -somewhere around the 8k range. The brooch is in the shape of a butterfly and has six natural opals. The largest oval shape oval measures approx. 9.4x7.4 mm, the head measures 6 mm diameter. Mostly green and blue play-of-color. I forgot to test the faceted red and blue stones but most likely imitation ruby and sapphires. Throughout the butterfly wings are half pearls set. There is even a pearl between the head and body. Please note there is some lines in the opal when I hold them up to light but my fingernail does not catch them and under magnification I don't see "a crack". Its possible they are internal or if they are surface reaching they very very slight. The back is so amazing. The wings are hinged with springs so you squeeze the wings together to open the prongs to clasp onto fabric. There is also a safety chain with pin. 1.75 in. wide 1.25 in. tall