This monogram is by British Heraldic Artist, J Gordon Smith from his book Monograms in Three and Four Letters. 

Monogram: MJC

Accents/Accessories: Large attached bail; Smooth finish; Rounded detailed floral edges with oxidization; Raised monogram

Size: 70 x 53 millimeters (2.76 x 2.09 inches)

Weight: 24.40 grams (0.86 ounces)