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Pearl Grading

Cultured Freshwater Pearls Grading Chart

Freshwater Pearls are one of the most popular types of Pearls used today in Pearl Jewellery. From their vast range of colour and sizes, Freshwater Pearls make an excellent choice for designers when used in Jewellery. Their competitive prices make it a very popular choice in today’s pearling industry. UMI Pearls uses Round to Near Round Freshwater Pearls which are considered the rarest and sought after Freshwater Pearls. UMI Pearls observes and follows the A-AAA grading system which is accepted internationally. Furthermore, UMI Pearls only accepts AAA as the highest grade possible and does not follow the superficial grades of AAA+ and AAAA which are not acknowledged by the respected industry professionals.

Pearl Grade Description
AAA
  • » High grade Freshwater Pearls representing the top 1% of pearls produced.
  • » Show case a very high and excellent Lustre
  • » Round in shape to the naked eye.
  • » Surface is 95% clean.
  • » Nacre of the Pearl is noticeably thick.
  • » Exhibits excellent matching.
AA+
  • » High grade Freshwater Pearls representing the top 5% of pearls produced.
  • » Showcase a very high Lustre.
  • » Near round in shape to round from a meter away to the naked eye.
  • » Surface is 90% clean.
  • » Exhibits excellent to very good matching.
AA
  • » Freshwater Pearls representing the top 10% of pearls produced today.
  • » Shape is near round to off round.
  • » Lustre is good to medium.
  • » Surface has slight blemishes covering less than 20% of the surface area.
  • » Exhibits good to average matching.
A
  • » Freshwater Pearls representing the top 20% of pearls produced today.
  • » Shape is near round to off round.
  • » Lustre is low to medium.
  • » Surface has blemishes covering less than 30% of the surface area.
  • » Exhibits good to average matching.

Cultured Akoya Pearls Grading Chart

For the Akoya grading scale, UMI Pearls observes and follows the A-AAA grading system which is accepted internationally. Furthermore, UMI Pearls only accepts AAA as the highest grade possible and does not follow the superficial grades AAA+ and AAAA which are not acknowledged by the respected industry professionals.

Pearl Grade Description
AAA
  • » Not less than 95% of pearl’s surface is spotless.
  • » Shape is perfect round.
  • » Lustre of the pearl is strong to very strong.
  • » Pearls displays very acute mirror like reflections.
  • » Nacre of the Pearl is noticeably thick
  • » The strand or earrings are matched to an excellent standard.
AA+
  • » Not less than 90% of pearl’s surface is spotless.
  • » Shape is round to near round.
  • » Lustre is good to strong
  • » Pearl exhibits good to acute reflections.
  • » Nacre of the Pearl is noticeably thick.
  • » The strand or earrings are matched to a good to excellent standard.
AA
  • » Not less than 80% of pearl’s surface is spotless.
  • » Shape is near round.
  • » Lustre is good to medium.
  • » Pearl exhibits good to moderate reflections.
  • » Nacre deepness is average.
  • » The strand or earrings are matched to a good to excellent standard.
A
  • » Not less than 70% of pearl’s surface is clean.
  • » Shape is near round to oval.
  • » Lustre is low to medium (Pearls seem “Chalky” in appearance).
  • » Pearl exhibits very slight and obtuse reflections.
  • » Nacre deepness is shallow.
  • » The strand or earrings are matched to a very fair standard.

Cultured Tahitian Pearls Grading Chart

UMI Pearls follows the Tahitian Pearl Grading standards which are used in French Polynesia – which is based on Government standard. This is sometimes referred to the “Tahitian system”. The Tahitian system uses pearls from a grade of A – D. To ensure that your experience is easier we have utilized it with the AAA-A system adopted at UMI Pearls and created by the late Kokichi Mikimoto.

A-D Top Gem Grading System A-AAA US Grading System Description
A AAA
  • » 90% of the Pearl’s surface is clean.
  • » Only 10% of pearl’s surface may show case minor, concentrated imperfections.
  • » Only a single deep inclusion permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is very high.
A/B AA+
  • » 80% of the Pearl’s surface is clean.
  • » Only 20% of pearl’s surface may showcase minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is high to very high.
B AA
  • » 70% of the Pearl’s surface is clean.
  • » Only 30% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set almost clean.
  • » Luster is high to very high.
C A+
  • » 40% of the Pearl’s surface is clean.
  • » Up to 60% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Deep inclusions are restricted to 10% of pearl’s surface.
  • » Luster is medium to very high.
D A+
  • » At least 60% of pearl’s surface will show case flaws.
  • » Deep inclusions and/ or white spots within inclusions on up to 20% of pearl’s surface.
  • » Luster is poor to very high.

***For Tahitian Pearls the Government of French Polynesia has set a minimum nacre thickness of 0.8 millimeters. Any Pearls that do not meet that requirement are destroyed and not permitted to be sold.

Cultured Golden South Sea Pearls Grading Chart

For the Golden South Sea Pearls grading chart, UMI Pearls follows the same grade for Tahitian Pearls as they are graded the same. UMI Pearls uses the A-AAA grading system when grading Cultured South Sea Pearls.

UMI Pearls does not subscribe to superfluous grades such as AAA+ and AAAA. These are not industry accepted grades.

A-D Top Gem Grading System A-AAA US Grading System Description
A AAA
  • » 90% of the Pearl’s surface is clean.
  • » Only 10% of pearl’s surface may show case minor, concentrated imperfections.
  • » Only a single deep inclusion permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is very high.
A/B AA+
  • » 80% of the Pearl’s surface is clean.
  • » Only 20% of pearl’s surface may showcase minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is high to very high.
B AA
  • » 70% of the Pearl’s surface is clean.
  • » Only 30% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set almost clean.
  • » Luster is high to very high.
C A+
  • » 40% of the Pearl’s surface is clean.
  • » Up to 60% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Deep inclusions are restricted to 10% of pearl’s surface.
  • » Luster is medium to very high.
D A+
  • » At least 60% of pearl’s surface will show case flaws.
  • » Deep inclusions and/ or white spots within inclusions on up to 20% of pearl’s surface.
  • » Luster is poor to very high.

Cultured White South Sea Pearls Grading Chart

For the White South Sea Pearls grading chart, UMI Pearls follows the same grade for Tahitian Pearls as they are graded the same. UMI Pearls uses the A-AAA grading system when grading Cultured South Sea Pearls.

UMI Pearls does not subscribe to superfluous grades such as AAA+ and AAAA. These are not industry accepted grades.

A-D Top Gem Grading System A-AAA US Grading System Description
A AAA
  • » 90% of the Pearl’s surface is clean.
  • » Only 10% of pearl’s surface may show case minor, concentrated imperfections.
  • » Only a single deep inclusion permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is very high.
A/B AA+
  • » 80% of the Pearl’s surface is clean.
  • » Only 20% of pearl’s surface may showcase minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set clean to almost clean.
  • » Luster is high to very high.
B AA
  • » 70% of the Pearl’s surface is clean.
  • » Only 30% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Only one or two deep inclusions permitted.
  • » Pearl should drill or set almost clean.
  • » Luster is high to very high.
C A+
  • » 40% of the Pearl’s surface is clean.
  • » Up to 60% of pearl’s surface may exhibit minor, concentrated imperfections.
  • » Deep inclusions are restricted to 10% of pearl’s surface.
  • » Luster is medium to very high.
D A+
  • » At least 60% of pearl’s surface will show case flaws.
  • » Deep inclusions and/ or white spots within inclusions on up to 20% of pearl’s surface.
  • » Luster is poor to very high.