Gemstone profile and identification guide

Freshwater Pearl

Freshwater pearls are cultured biogenic gems produced in freshwater mollusks.

3 Mohs White, Pink Organic Gem Material (Cultured Freshwater Pearl)

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Overview

Freshwater pearls are cultured biogenic gems produced in freshwater mollusks.

Did you know? Contemporary freshwater pearl farming transformed global pearl affordability and variety.

Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.

Identification

Name: Freshwater Pearl

Scientific classification: Organic Gem Material (Cultured Freshwater Pearl)

Hardness: 3 Mohs

Transparency: opaque

Lustre: pearly

Crystal system: Biogenic aragonite/calcite aggregate

Primary colour: White

Secondary colour: Pink

Colour family: Whites & Neutrals

Surface texture, drill-hole structure, and nacre behavior under magnification support identification.

Verification Status

Status: verified-core-fields

Reference priority: GIA, Gem-A, Mindat, International Gem Society

Core identity, locality, and physical-property fields reviewed against standard gemological references.

Trade-name entries include treatment/composition disclosures where applicable.

Physical Properties

Hardness category: soft

Hardness value: 3 Mohs

Chemical composition: Calcium carbonate with conchiolin

Crystal system: Biogenic aragonite/calcite aggregate

Common locations: China (dominant), with smaller production in other freshwater aquaculture regions

Learn more: Gem-A gemstone education resources.

Colour Variations

Cultured freshwater pearls in white, cream, pink, and lavender tones with nacre lustre.

Optical effects: Orient

Detailed Gemology

Mineral species: Biogenic pearl material

Mineral group: Organic gem material

Chemical formula: Calcium carbonate with conchiolin

Mohs hardness: 3

Crystal system: Biogenic aragonite/calcite aggregate

Lustre: pearly

Transparency: opaque

Streak: White

Cleavage: Not applicable

Fracture: Uneven

Specific gravity: 2.60-2.85

Refractive index: Spot values commonly near 1.53 (structure-dependent)

Optical phenomena: Orient and nacre lustre

Colour range: White, cream, pink, lavender, peach

Common inclusions: Surface growth marks and nacre irregularities

Geological environment: Freshwater aquaculture environments

Principal mining regions: China (dominant), with smaller production in other freshwater aquaculture regions

Important commercial sources: Modern freshwater cultured pearl production is dominated by China

Historical significance: Major category in modern pearl jewelry market.

Common treatments: Bleaching, dyeing, and lustre enhancement are common.

Synthetic or imitation forms: Shell pearls, glass pearls, and plastic-coated imitations are common.

Common look-alikes: Imitation pearls and low-nacre composites

Jewellery uses: Used in strands, earrings, pendants, and fashion-to-fine jewellery.

Care recommendations: Soft and chemically sensitive; wipe after wear and avoid perfume, acids, and dry heat.

Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Freshwater Pearl.

Formation

Nacre layers form around implanted or induced nuclei/tissue in freshwater aquaculture systems.

Origin

Modern freshwater cultured pearl production is dominated by China

Uses

Best for: Used in strands, earrings, pendants, and fashion-to-fine jewellery.

Ideal uses: Pearl strands and gentle-wear jewellery with regular maintenance.

Care

Soft and chemically sensitive; wipe after wear and avoid perfume, acids, and dry heat.

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