A three strand gold, silver, diamond and natural pearl necklace with an exceptionally large blister pearl

Circa 1900
The graduating three-strand natural pearl necklace centered by a rose-cut diamond and blister pearl set tortoise, suspending a pear-shaped pearl, to an old-cut diamond clasp and rose-cut diamond mounts, including a NEL (Dutch Gemstone Lab) Leiden certificate stating that the pearls are natural and untreated, numbered P5612, the blister pearl not tested.
Total diamond weight approx. 0.60 ct (clasp)
Blister pearl spread approx. 15 x 12 mm (not tested)
Pear-shaped pearl L. approx. 8.7 mm
Pearls diam. approx. 2.5-5 cm
Gross weight approx. 31 gr.
L. approx. 36 cm
Measured, graded and weighed in the mount