So, question to our pearly science guys; is any part of zeide's post horse-pooky?
Let's discuss this question for a moment.
Hi,
Actually, most of the famous pearls of crown jewel collections are indeed freshwater pearls and not saltwater as they are often declared to be. Freshwater pearls can be of varying quality, but so can saltwater. The preference of saltwater pearls hails back to George Frederik Kunz who proclaimed in his Book of the Pearl that they are rounder, harder, and more durable but only on his word. There is no scientific evidence to confirm that except some to the contrary.
Grading as we know it provides the market with rounder pearls from varied source pools. Every natural pearl found does not end up on the end of a chain or set in a bezel, so there is no possible way she could know what was rejected from harvested lots centuries ago.
Pearls are like bones. The harder they are, the more brittle they become and that's because they contain less protein and more calcite. Pearls are 2.5 to 4.5 mohs, which is the single most widest margin for extra-crystalline structure among all of the gems. Given that point alone, there is no possible way that differences between SW or FW can be generalized in that manner. While softer pearls are more vulnerable to dents or scratches, they are actually more durable to shock forces than hard pearls which may otherwise crack or break.
A perfect example for everyone to relate to are nuclei. Giant Clams (Tridacacna gigas) are too hard, Pacific Oysters (Crassostrea gigas) are too soft and as we all know freshwater Washboard Mussels (Megalonaias gigantean) are ideal, therefore the relationship between them is relative to species, not the presence or absence of a single chemical property.
For most of history freshwater pearls were preferred probably because their higher manganese content makes them phosphorescent (glow in the dark). Freshwater pearls from high latitudes are also known for their luster maintenance. That means, when they dry out and get dull, they can simply be rehydrated and made lustrous again by wearing them (manganese-calcium compounds are hygroscopic). Although sodium chloride (salt) is also hygroscopic, there is no salt in saltwater pearls. Lower-manganese saltwater pearls thus do not glow in the dark, however, most natural (not cultured) saltwater pearls are estuary pearls that also have decent manganese contents.
Nonsense on every level. "preferred probably" means perception upon assumption, not fact. First, phosphorescent is an ambiguous term. If she was as learned as she claims, she would have used the term chemiluminescence. In reality, even phosphorus is chemiluminescent in nature. The same ambiguity relates to bioluminescence, the emission of light by living organisms, namely plankton. Besides that, even in modern science, manganese content is neither mutually exclusive nor a collectively exhaustive factor in determining the aquatic origin of pearls. Annecdotal studies allude to slight elevations of manganese in FWP in broad terms, but it's definitely not the standard for individual pearls.
Secondly, the parallel drawn between higher latitudes and luster is ridiculous. If this were true all of my boreal pearls would be lustrous and world class. In nearly every instance, luster is indirectly proportional to age of the mollusk, not it's ecology, range or distribution. Any subtle difference in the same species between regions is mainly relative to genetics, not environment.
Lastly, most natural pearls being estuarine and having higher manganese content as a result is unfounded and/or over generalized. Truth being, natural pearls are collectively harvested from a multitude of zones, even though some regions may have predominance one way or the other. I will support this by suggesting that it's not necessarily water quality that matters, it's whether the species can survive being buried in sediments. Most pearl oysters and mussels are epifaunal. Meaning they live on the surface of the substrate, (ie) rocks, vegetation or on the sea floor and lake bottom. Clams, worms etc. are infaunal, living within the substrate.
The ones from the Ganges delta can even have higher manganese contents than most freshwater pearls. If kept well, i.e. in a moist environment, your freshwater pearls can last millennia.
This makes no sense whatsoever. Any saltwater pearl from anywhere can have compounds higher or lower than freshwater or vice versa. She singled out a region, yet provided no supporting evidence. To boot, the second sentence implies that because of manganese, FWP kept in a moist environment will last virtually forever. There is no evidence of manganese as a preservative, no less "moist environment" is a poor usage of the term -relative humidity-, where only a narrow window of atmospheric conditions serve conservation well.
