9K GOLD DOG CLIP CLASP FINDINGS ANTIQUE VICTORIAN C1890.
The gold mark can be found to the one side but is quite badly rubbed, there's a maker's mark M&M. Good secure clasp with a good spring.
Size 2.4 x 0.6 cm or 0.9 x 0.2 inches.
Weight 2.4 grams or 1.5 penny weight.