Cultured Pearl Gemstone & Information | Gemopedia by JTV | Gemopedia™
Pearls are the only gems that are grown inside living creatures, so rather than being mined like other gems, pearls can be farmed and harvested. Pearls have been harvested from mollusks for thousands of years, either by chance or, more recently, purposely through culturing. From the start of mankind's love affair with pearls, they have been symbolic of class, purity, refinement, and wealth, but modern designs with fashionable new pearl shapes and colors are helping pearls appeal to a broader audience. They truly are not just your grandmother's pearls anymore.
White, Cream, Golden, Silver, Gray, Brown, Black
Cultured-pearl classificationCommonNameCultured PearlSpeciesNAVarietyCultured PearlColorsWhite, Cream, Golden, Silver, Gray, Brown, BlackAlternateNamesGemstoneGroupsKeySeparationsrefractive index, birefringence blink, specific gravity 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.ClassificationCommentsMajor classifications include natural/cultured and saltwater/freshwater. Major types of cultured pearls include Akoya, Tahitian, South Sea and Freshwater.
Cultured-pearl chemistry & crystallographyChemicalNamecalcium carbonate + conchiolin and waterChemicalFormulaCaCO3SynthesisCrystalSystemNAChemistryClassificationOrganicNatureCulturedCrystallinityNon-CrystallineChemistryComments
Cultured-pearl optical propertiesTransparencyTranslucent - OpaqueDispersionOpticalCommentsRefractiveIndex1.53-1.685Birefringence0.155-0.155OpticCharacterNAOpticSignNAPolariscopeReactionAggregate (AGG)FluorescenceSWUV: inert to strong light blue, yellow, green or pink
LWUV: inert to strong light blue, yellow, green or pinknatural black: weak to moderate red to orangy red to brownish redLa Paz: strong redCCFReactionPleochroismNone
Cultured-pearl characteristic physical propertiesHardness3.5-4CharacteristicCommentsStreakSpecificGravity2.72-2.78ToughnessFairInclusionsCultured pearls will have an iridescent surface. If the pearl is drilled you can inspect the hole to look for bead nucleus.LusterPearlyStabilityPoorFractureUnevenCleavageNone