Old cultured pearl necklaces
Recently, the SSEF received three pearl necklaces for testing. Each necklace had a clasp containing diamonds and what appeared to be a sapphire. The pearls were graduated in size, with a small knot separating each one.
Cultured South Sea pearls with small beads
Identifying beaded cultured pearls is usually quite straightforward, as such pearls often contain a large bead made from a freshwater shell with a nacre layer only 1.5 mm or less thick.
Age dating of gemstones, pearls and corals (2024)
Presentation by Dr. Michael S. Krzemnicki at the 2024 Gem-A conference in London in November 2024.
Visit to Japan’s pearl farms
Having attended the IGC conference in Tokyo in October 2023, Dr. Michael S. Krzemnicki and Dr. Laurent E. Cartier took some time to travel south to visit the cultured pearl trading hub of Kobe and pearl farmers in Mie prefecture.
Exceptional non-nacreous pearls and pearl jewellery
Over the past few months, we have again analysed a number of outstanding, historic, or gemmologically interesting pearls. These include natural pearls from gastropods and non-nacreous shells.
DNA Fingerprinting and age dating of historic natural pearls: a combined approach
DNA Fingerprinting and age dating of historic natural pearls: a combined approach. IGC 2023 Proceedings, 157-158.
Saltwater pearl with barium
Recently, the SSEF received a button-shaped pearl of 7.5 ct for testing. Based on X-ray radiography and a UV-Vis-NIR reflectance spectrum, the pearl was easily identified as a saltwater natural pearl from the species Pinctada margaritifera.
Cultured pearl with unconventional bead material
Recently, we received a round pearl for testing which exhibited an excellent surface quality and a remarkable size of 24 mm in diameter. Interestingly, its weight of 60 ct was rather low for such a pearl (resulting in a calculated specific gravity of approx. 1.61 instead of 2.715 considered standard for a pearl
Assembled blisters and shells used to imitate pearls
Since historic times, natural pearls have been treasured and considered symbols of wealth and beauty. When harvesting (natural) pearls, one may find not only a pearl inside a shell, but also blister pearls and quite often blisters. A pearl has grown completely wrapped in a pearl sac in the mollusc, whereas a bl
Pearls & diamonds: a royal selection
The SSEF is known worldwide as a leading authority in gem testing, and as such we have the great pleasure to scientifically analyse some of the most prestigious and important jewellery before it is offered up for auction or in private sales. Apart from testing the gem materials in such jewellery, we are often i