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GB/T 18781-2023: Cultured pearl grading
Status: Valid GB/T 18781: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| GB/T 18781-2023 | English | 319 |
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Cultured pearl grading
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GB/T 18781-2023
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| GB/T 18781-2008 | English | 479 |
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Cultured pearl grading
| Obsolete |
GB/T 18781-2008
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| GB/T 18781-2002 | English | 519 |
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Cultured pearl grading
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GB/T 18781-2002
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PDF similar to GB/T 18781-2023
Basic data | Standard ID | GB/T 18781-2023 (GB/T18781-2023) | | Description (Translated English) | Cultured pearl grading | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | Y88 | | Classification of International Standard | 39.060 | | Word Count Estimation | 15,118 | | Date of Issue | 2023-05-23 | | Date of Implementation | 2023-12-01 | | Older Standard (superseded by this standard) | GB/T 18781-2008 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 18781-2023: Cultured pearl grading---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
ICS 39:060
CCSY88
National Standards of People's Republic of China
Replacing GB/T 18781-2008
pearl grading
Released on 2023-05-23
2023-12-01 implementation
State Administration for Market Regulation
Released by the National Standardization Management Committee
table of contents
Preface I
1 Scope 1
2 Normative references 1
3 Terms and Definitions 1
4 Pearl Quality Factors and Grades 3
4:1 Color 3
4:2 Size 4
4:3 Shape level 4
4:4 Gloss level 4
4:5 Finish class 5
4:6 Pearl layer thickness level 5
4:7 Quality 6
5 Pearl Level 6
5:1 Pearl grade classification 6
5:2 Grading of Jewelry Grade Pearls6
5:3 Handicraft grade pearls6
6 Inspection method 7
6:1 Color 7
6:2 Size 7
6:3 Shape 7
6:4 Gloss 8
6:5 Finish 8
6:6 Bead thickness8
6:7 Compatibility 9
6:8 Quality 9
7 Grading staff requirements 9
8 Grading report or certificate basic content 9
Appendix A (Normative) Thickness grade of nucleated nacre from Pinctada martensii 11
foreword
This document is in accordance with the provisions of GB/T 1:1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents"
drafting:
This document replaces GB/T 18781-2008 "Pearl Grading": Compared with GB/T 18781-2008, except for structural adjustments and editorial changes
In addition to the dynamics, the main technical changes are as follows:
--- Changed the scope (see Chapter 1, Chapter 1 of the:2008 edition);
---Changed natural pearls, pearls, seawater pearls, freshwater pearls, bead core, nacre, nacre thickness, color matching, iridescence, diameter difference
Terms and Definitions for Score, Blemish, Smoothness, Match, Pearl Master Sample, Pearl Trim, and Mixed Pearls (see Chapter 3,
Chapter 3 of the:2008 edition);
--- Added the terms and definitions of nucleated pearls, non-nucleated pearls, nacre, nacre thickness ratio, and pearl grading (see Chapter 3);
--- Change "quality factors and grades of seawater pearls" and "quality factors and grades of freshwater pearls" to "quality factors and grades of pearls"
Gender (see Chapter 4, Chapter 4 and Chapter 5 of the:2008 edition);
--- Changed the color (see 4:1, 4:1 and 5:1 of the:2008 version);
---Changed the expressions of shape level, gloss level, smoothness level, bead thickness level and matching level (see 4:3~4:6,
5:2:3:2, Chapter 4, Chapter 5 and 6:4:2:2 of the:2008 edition);
--- Increase the thickness level of non-nuclear pearl layer and the thickness level of nucleated pearl layer (see 4:6:1 and 4:6:2);
---Changed the minimum level requirements for the quality factor of jewelry-grade pearls (see 5:2:1, 6:2 of the:2008 edition);
---Changed the inspection methods for color, gloss, smoothness and bead thickness (see Chapter 6, Chapter 7 of the:2008 edition);
--- Increase the gloss level division rules (see 6:4:1);
--- Added the calculation method of bead thickness ratio (see 6:5:2);
--- Added quality inspection methods (see 6:8);
---Changed the basic content of the grading report or certificate (see 8:1, 9:1 of the:2008 edition);
---Deleted the expression method and identification of the quality factor level (see 9:2 and Chapter 10 of the:2008 edition);
--- Added the thickness level of nucleated pearl nacre produced by Pinctada martensii (see Appendix A):
Please note that some contents of this document may refer to patents: The issuing agency of this document assumes no responsibility for identifying patents:
This document is proposed by China National Light Industry Council:
This document is under the jurisdiction of the National Jewelry Standardization Technical Committee (SAC/TC256):
This document was drafted by: Guangxi Zhuang Autonomous Region Product Quality Inspection Institute, Beihai Product Quality Inspection Institute, National Jewelry and Jade Headquarters
Jewelry Inspection Group Co:, Ltd:, Zhejiang Academy of Product Quality and Safety Sciences, Beijing Guoshou Jewelry Testing Co:, Ltd:, Beijing Gaodezhu
Treasure Appraisal Research Institute Co:, Ltd:, Zhuji City Market Supervision Administration, Zhejiang Pearl Industry Association, Shenzhen Moting Medical Technology Co:, Ltd:, Zhejiang
Jiangfangyuan Testing Group Co:, Ltd:
The main drafters of this document: Lu Dongnong, Tao Jinbo, Cao Huasong, Lu Ming, Ma Yubo, Zeng Ming, Xie Shanshan, Zhou Danyi, He Jinfeng, Yan Xuejun,
Xu Chong, Su Jun, He Tieyuan, Qu Gang, Liang Haili, Wang Yan, Wang Siyu, Li Yi, Yan Jun, Wang Hui:
The release status of previous versions of this document and the documents it replaces are as follows:
---It was first published as GB/T 18781-2002 in:2002 and revised for the first time in:2008;
--- This is the second revision:
pearl grading
1 Scope
This document specifies the quality factors and grades of cultured pearls (hereinafter referred to as "pearls"), pearl grades, requirements for grading personnel, grading reports or
The basic content of the certificate and other requirements describe the inspection method:
This document is applicable to quality evaluation activities related to pearl production and trade:
This document does not apply to the grading of irradiated, dyed, etc: pearls and composite pearls:
The grading of natural pearls and pearl ornaments can be implemented by reference:
Note: Assembled pearls refer to pearls that are spliced together with other objects and give people an overall impression:
2 Normative references
The contents of the following documents constitute the essential provisions of this document through normative references in the text: Among them, dated references
For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to
this document:
GB/T 16552 Names of Jewelry and Jade
GB/T 16553 Identification of Jewelry and Jade
GB/T 23886 Method for Determination of Pearl Pearl Layer Thickness Optical Coherence Tomography
3 Terms and Definitions
GB/T 16552, GB/T 16553, GB/T 23886 and the following terms and definitions apply to this document:
3:1
natural pearl natural pearl
Molluscs such as shellfish or mussels naturally secrete the formation of nacre solidification without human intervention:
Note 1: It is mainly composed of calcium carbonate (mainly aragonite), organic matter (mainly conchiolin), and secondly contains water, various trace elements, etc:, in the form of concentric layers
Or concentric layer radial structure, showing pearly luster:
Note 2: According to different growth waters, it can be divided into natural seawater pearls and natural freshwater pearls: Natural pearls produced in seawater are natural seawater pearls: exist
Natural pearls produced in fresh water are natural freshwater pearls:
3:2
Cultured Pearl 1) culturedpearl
Molluscs such as shellfish or mussels are intervened by human factors to secrete and solidify nacre:
1) According to GB/T 16552, "cultured pearls" can be referred to as "pearls" for short, and "natural" is added before pearls to specifically refer to natural pearls: The pearls referred to in this document are all special
Refers to cultured pearls:
Note 1: It is mainly composed of calcium carbonate (mainly aragonite), organic matter (mainly conchiolin), and secondly contains water and various trace elements: nacre
Concentric layered or radial structure of concentric layers, showing pearly luster:
NOTE 2: For all pearls, the nacre is produced from the secretions of living molluscs: Human factors intervention is just to start the process, regardless of
Is the use of insert core, or insert, or other ways: According to different growth waters, it can be divided into seawater pearls and freshwater pearls: According to the presence or absence of beads
Nuclei can be divided into nucleated pearls and non-nucleated pearls: According to whether it is attached to the shell, it can be divided into free type pearls and attached shell type pearls:
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