DEMANTOID GARNET AND DIAMOND CLOVER BROOCH, CIRCA 1880
Set throughout with cushion-shaped, old brilliant and rose-cut diamonds, the trefoil leaf accented by three old-cut demantoid garnets, principal diamond very approximately 1.20 carats, demantoid garnets very approximately 3.00 - 3.60 carats total, two diamonds deficient, one single-cut diamond replacement, length 6.0cm
Footnotes:
Demantoid garnet was discovered in the Central Ural Mountains of Russia in 1864 and this mine remained the only source for the gem until the mid-1990s. Demantoid
garnet occurs as very small grains in the host rock, making it very difficult to find large size gem-quality rough. Faceted material tends to be small for the most part and it is rare to find antique stones over 1ct. See: Wm. Revell Phillips and Anatoly S. Talantsev 'Russian Demantoid, Czar of the Garnet Family,' Gems & Gemology, Summer 1996, Vol. 32, No. 2.

The demantoid garnets are medium olive to lively, bright green hues, the central demantoid garnet at the top of the trefoil motif being the most vibrant. Under 10 X magnification, a few natural mineral inclusions seen with some abrasions to the facets/facet edges. Principal diamond assessed in mount and estimated SI2 clarity, J/K colour. Two diamonds missing. Top leaf with a small single-cut diamond replacement (located just below one of the missing stones). Some light surface wear including pitting visible on unmarked/untested silver and gold. Later pin fitting and rhodium plating. Overall in good condition. Gross weight approx. 11.0 grams.

Very approximate dimensions of demantoid garnets (gauged in settings), from left to right:
6.2 x 6.2 x 4.2mm
6.5 x 6.5 x 4.0mm (centre)
6.2 x 6.2 x 3.5mm

Remaining cushion-shaped, old brilliant and single-cut diamonds very approximately 3.25 carats total.