Freshwater Pearl Gemstone & Information | Gemopedia by JTV | Gemopedia™
Although freshwater pearl cultivation originated in Japan, China is now the world's major producer of freshwater pearls. The humble freshwater mussel, while not as widely celebrated as its cousin the oyster, is capable of producing high-quality pearls. Generally speaking, freshwater pearls tend not to have the luster and shine of saltwater, but do form in a variety of shapes and colors, and are typically sold at lower prices.
Gray, White, Cream, Yellow, Pink, Purple With Blue, Green Overtone, Orient
Freshwater-pearl classificationCommonNameFreshwater PearlSpeciesNAVarietyFreshwater PearlColorsGray, White, Cream, Yellow, Pink, Purple With Blue, Green Overtone, OrientAlternateNamesKasumiga PearlGemstoneGroupsKeySeparationsAppearance, RI, birefringence blink and magnification. A "tooth test" is commonly used in which a pearl is rubbed against a tooth; if gritty, this is an indication that the surface is nacre, versus plastic and glass imitations that feel smooth.ClassificationCommentsTypical size of freshwater pearls are 2 to 13mm. They are produced by the Hyriopsis schlegeli, Hyriopsis cumingli and Cristaria plicata mussels. Kasumiga pearls were farmed in the Japanese Lake Kassumigaura in the hybrid Hyriopsis schlegeli/ Hyriopsis cumingli mussel.
Freshwater-pearl chemistry & crystallographyChemicalNamecalcium carbonate + conchiolin and waterChemicalFormulaCaCO3SynthesisCrystalSystemNAChemistryClassificationOrganicNatureCulturedCrystallinityChemistryComments
Freshwater-pearl optical propertiesTransparencyTranslucent - OpaqueDispersionOpticalCommentsRefractiveIndex1.53-1.685Birefringence0.155OpticCharacterNAOpticSignNAPolariscopeReactionAggregate (AGG)FluorescenceSWUV: Variable
Freshwater-pearl characteristic physical propertiesHardness2.5-4CharacteristicCommentsStreakSpecificGravity2.72-2.78ToughnessGoodInclusionsIf the pearl is drilled you can inspect the hole to look for lack of bead nucleus.LusterDullStabilityPoorFractureUnevenCleavageNone