This standard is applicable to the production, trade, quality evaluation and other activities of cultured pearls, and is not applicable to the grading of cultured pearls after irradiation and dyeing.
The classification of natural pearls can also be referred to. The clauses in the following documents become the clauses of this standard by reference. All subsequent modifications (excluding errata) or revisions of dated reference documents are not applicable to this standard. However, parties who have reached an agreement according to this standard are encouraged to study whether the latest versions of these documents can be used. For undated reference documents, the latest edition is applicable to this standard.
GB/T 16552 Names of Jewelry and Jade
GB/T 16553 jewelry and jade appraisal GB/T 16552, GB/T 16553 and the following terms and definitions are applicable to this standard.
3. 1 natural pearls
Natural secretions in shellfish or mussels that do not contain human factors. They are composed of calcium carbonate (mainly aragonite), organic matter (mainly conchiolin) and water. They are concentric layered or concentric layered radial structures with pearl luster.
According to the different growing waters, it can be divided into natural seawater pearls and natural freshwater pearls.
Natural pearls produced in seawater are natural seawater pearls.
Natural pearls produced in fresh water are natural freshwater pearls.
3.2 cultured pearls
The nacre is formed in shellfish, mussels and other animals. The nacre is concentric layered or concentric layered radial structure, which is composed of calcium carbonate (mainly aragonite), organic matter (mainly conchiolin) and water. For all cultured pearls, the nacre is secreted by living mollusks. Manual intervention only starts this process, whether it is nuclear insertion or chip insertion.
According to different growing waters, it can be divided into seawater cultured pearls and freshwater cultured pearls.
According to the presence or absence of nucellar, it can be divided into nucleated cultured pearls and seedless cultured pearls.
According to whether shells are attached or not, they can be divided into free cultured pearls and attached cultured pearls.
3.2. 1 cultured pearls in seawater
Cultured pearls formed in shellfish in seawater.
According to different shellfish species, it can be divided into different subtypes: marine cultured pearls of Pinctada martensii, marine cultured pearls of Pinctada papillata, marine cultured pearls of Pinctada nigromaculata and marine cultured pearls of Penguin.
3.2.2 Freshwater cultured pearls
Cultured pearls formed in freshwater mussels.
According to different species of mussels, they can be divided into different subtypes: freshwater cultured pearls of Hyriopsis cumingii, freshwater cultured pearls of freshwater cultured pearls of freshwater mussels and freshwater cultured pearls of freshwater cultured pearls of toothless mussels.
3.2.3 Korean pearls cultivated in shells
Cultured pearls are produced by deliberately implanting hemispherical or three-quarters spherical non-spherical pearl cores into the shells of marine mother-of-pearl or freshwater mussels, and the flat side of the pearl cores often sticks to the shells.
3.3 nucellar nucleus
Artificial implants in cultured pearl nuclei.
3.4 nacre in nacre
The outer part of nucellar cultured pearls is mainly composed of calcium carbonate (mainly aragonite), organic matter (mainly conchiolin) and water, with concentric layered or concentric layered radial structure.
3.5 nacre thickness
Vertical distance from the outer layer of pearl core to the surface of cultured pearl.
3.6 color color
Comprehensive characteristics of body color, companion color and halo color of cultured pearls.
Body color: the color produced by the selective absorption of white light by cultured pearls.
Companion color: One or more colors floating on the surface of cultured pearls.
Halo: a floating rainbow color formed on or under the surface of cultured pearls.
3.7 Percentage of Diameter Difference
Percentage of the difference between the maximum diameter and the minimum diameter and the difference between the average of the maximum diameter and the minimum diameter.
3.8 Size
The size of a single cultured pearl.
3.9 shape shape
External morphology of cultured pearls.
3. 10 luster
The intensity of reflected light on the surface of cultured pearls and the clarity of images.
3. 1 1 defects
The surface of cultured pearls is not smooth and ugly.
The common defects on the surface of cultured pearls are: waist line, bulge (papule, tail), depression (flat head), wrinkle (furrow), breakage, notch, spot (black spot), needle pinch mark, scratch, peeling mark, crack and pearl scar.
3. 12 surface finish
The total smoothness and cleanliness of cultured pearl surface are determined by the size, color, location and number of defects.
3. 13 matching attribute
The coordination degree of cultured pearls in shape, luster, smoothness, color and size.
3. 14 mother pearl as standard sample
Comparative standard samples used to determine the quality factor grade of cultured pearls. There are two kinds: freshwater cultured pearl standard sample and seawater cultured pearl standard sample.
3. 15 cultured pearl jewelry
Jewelry made of cultured pearls through threading, bonding and precious metal inlay. Including beads (necklaces, bracelets, bracelets, rings), rings, earrings, hair accessories, foot accessories, clothing (brooches, tie clips, belt buckles) and so on.
3. 16 Split cultured pearls mabe pearls
Artificially processed products, the outer layer or upper part is cultured pearls, and other parts are cultured pearls or other substances. 4. 1 color
4. 1. 1 The colors of cultured pearls are divided into the following five series, including various body colors.
A) White series: pure white, milky white, silvery white, porcelain white, etc.
B) Red series: pink, light rose and lavender.
C) Yellow series: light yellow, beige, golden yellow, orange yellow, etc.
4. 1.2 mariculture pearls may have associated colors, such as white, pink, rose, silvery white or green.
4. 1.3 There may be halo on the surface of cultured pearls, which can be divided into strong halo, obvious halo and halo.
4. 1.4 color description: body color description is the main one, accompanied color and halo color description are the auxiliary ones.
Round, round and nearly round mariculture pearls are represented by the minimum diameter, other mariculture pearls are represented by the maximum size multiplied by the minimum size, and loose pearls can be represented by the pore size range of pearl sieve. Shape grade of cultured pearls in seawater
Description of quality requirements for shape rules (diameter difference percentage%)
Perfect circle A 1 ≤ 1
Circle A2 ≤5
Closed circle A3 ≤ 10
Ellipse B > 10 can be a drop shape or a pear shape.
Flat C has symmetry, and one or both sides are almost flat.
4.4 glossiness
Smoothness of marine cultured pearls
Gloss grade quality requirements
The extremely strong A-reflected light is particularly bright, sharp and uniform, with a mirror-like surface and clear image.
Strong B reflected light is bright, sharp and uniform, and the image is very clear.
C reflected light is bright, and objects can be seen on the surface.
Weak D reflects light weakly, and the surface can illuminate the object, but the image is blurred.
4.6 Weld bead thickness grade
See Table 4 for the classification of weld thickness grades.
Table 4 nacre thickness grade quality requirements of mariculture pearls mm extra-thick A ≥0.6 thick B≥0.5 C≥0.4 thin D ≥0.3 ultra-thin E < 0.3 5 Quality factors and grades of freshwater cultured pearls.
5. 1 color
5. 1. 1 The colors of freshwater cultured pearls are divided into the following five series, including various body colors.
A) White series: pure white, milky white, silvery white, porcelain white, etc.
B) Red series: pink, light rose, light purple, etc.
C) Yellow series: light yellow, beige, golden yellow, orange yellow, etc.
D) Black series: black, blue-black, gray-black, brown-black, purple-black, brown-black, iron-gray, etc.
E) Others: purple, brown, cyan, blue, brown, purplish red, green yellow, light blue, green, bronze, etc.
5. 1.2 Freshwater cultured pearls may have associated colors, such as white, pink, rose, silvery white or green.
5. 1.3 There may be halo on the surface of freshwater cultured pearls, which can be divided into strong halo, obvious halo and halo.
5. 1.4 color description: body color description is the main one, accompanied color and halo color description are the auxiliary ones.
5.2 dimensions
Round, round and nearly round freshwater cultured pearls are represented by the minimum diameter, other freshwater cultured pearls are represented by the maximum size multiplied by the minimum size, and loose pearls can be represented by the pore size range of pearl screen. 5.3. 1 Freshwater seedless cultured pearls with shape grade
See Table 5 for the shape classification of freshwater seedless cultured pearls. Quality requirements for shape category and grade (percentage of diameter difference) Remarks: Circular perfect circle A 1 ≤3 circle A2 ≤8 near circle A3 ≤ 12 oval short ellipse B 1 ≤20 long ellipse B2 > 20. The pear-shaped flat height C 1 ≤20 is symmetrical, and one or both sides are approximately plane low C2 >；; Table 5 Shape grades of freshwater seedless cultured pearls
5.3.2 Shape grade of freshwater nucleated cultured pearls
See table 1 for the shape classification of mariculture pearls. See Table 6 for the classification of glossiness.
Table 6 The glossiness of freshwater cultured pearls requires excellent quality. A reflected light is bright, sharp and uniform, and the image is clear. Strong B reflects light, while surface energy can see that the reflected light of C in the object image is not bright, while surface energy can see the object, but the image is blurred. The weak D-reflected light is all diffuse light, with dull surface gloss and almost no image. The classification of smoothness grades is shown in Table 7.
Table 7 Smoothness of Freshwater Cultured Pearls The smoothness of quality requires no flaws. A. The surface is smooth and delicate, and it is extremely difficult to observe surface defects with naked eyes. There are few defects like acupuncture on the surface. It is difficult to observe tiny defects with the naked eye. Defects can be easily observed with the naked eye. D, obvious defects, accounting for less than a quarter of the surface area. E, obvious defects, serious defects accounted for more than a quarter of the surface area. Remarks on quality requirements (percentage of diameter difference).
Perfect circle A 1 ≤ 1
Circle A2 ≤5
Closed circle A3 ≤ 10
Ellipse B > 10 can be a drop shape or a pear shape.
Flat C has symmetry, and one or both sides are almost flat.
Irregular D-shape is extremely irregular, usually with uneven surface and no obvious symmetry, which may be due to the similar shape of an object in 6. 1 cultured pearls.
According to the quality factors of cultured pearls, cultured pearls used for decoration are divided into two grades: jewelry-grade cultured pearls and handicraft-grade cultured pearls.
6.2 Minimum requirements for quality factors of jewelry-grade cultured pearls
6.2. 1 Gloss grade: medium (c).
Finishing layer:
Cultured pearls with a size over 9mm (including 9mm): Defect (D).
Cultured pearls with a size below 9mm: small defects (c).
6.2.3 nacre thickness (nucleated cultured pearls): thin (d).
6.3 Craft-grade cultured pearls
Those that fail to meet the requirements of 6.2 are craft-grade cultured pearls.
6.4 Classification of Jewelry-grade cultured pearls
6.4. 1 Classification of single cultured pearl ornaments cultured pearls
Determine the grade according to the requirements of quality factors in Chapter 4 and Chapter 5.
6.4.2 Classification of cultured pearls in multi-grain cultured pearl ornaments
Includes the determination of the overall quality factor level and the determination of the matching level.
Determination of overall quality factor level
A) determining the single quality factor level of each cultured pearl in the ornament
B) Count the percentage of cultured pearls in the same level of each single quality factor.
C) When the percentage of a quality factor level higher than a certain level is not less than 90%, the level is defined as the overall quality factor level.
6.4.2.2 matching level determination
Matching level determination
Matching level quality requirements
It's good. A quality factors such as shape, luster and smoothness should be consistent. Colors and sizes should be harmonious and beautiful or gradual. The eyelet is centered, straight, smooth and free of burrs.
Good B has slightly different quality factors such as shape, luster, smoothness, etc., the color and size are coordinated and basically gradual, and there is no burr in the center of the hole.
General c color, size, shape and luster. There are obvious differences in quality factors such as smoothness, slightly skewed eye hole and raw edge of 7. 1 color.
Under the background of gray or white, avoid bright colored objects, adopt northern sunlight or fluorescent lamp with color temperature of 5500 K ~ 7200 K, the distance from the tested sample is 20 cm ~ 25 cm, and the distance from the naked eye to the tested sample is 15 cm ~ 20 cm, and roll cultured pearls to find out the main color, that is, body color; From the light reflected from the surface of cultured pearls, find out whether cultured pearls have companion color and halo color; Observe and record the body color, companion color or halo color of the test sample.
7.2 dimensions
7.2. 1 Accurate Measurement Method (Arbitration Method)
7.2. 1. 1 measuring instrument
Measuring tool with dividing value not greater than 0.02 mm
7.2. 1.2 operation steps
A) clean the test sample.
B) Measure and record the maximum diameter and minimum diameter with measuring tools.
7.2. 1.3 notation
Conventional, round and nearly round cultured pearls are represented by the minimum diameter, while other shapes give the maximum and minimum sizes. For example: 8.0 mm × 6.0 mm
Screening method
Only suitable for loose beads in bulk.
7.2.2. 1 instruments and equipment
The continuous interval of aperture specification is not more than 0.5mm. ..
7.2.2.2 operation steps
A) clean the test sample.
B) Screening the test sample.
C) Until the tested sample is unqualified.
7.2.2.3 notation
The size of the tested sample is expressed by the aperture specifications of the two screens through which the tested sample can pass and cannot pass. For example: 5.0 mm to 5.5 mm.
7.3 shape
According to the measured data, the percentage X(%) of diameter difference is calculated according to the formula (1), and the shape grade of cultured pearls is determined.
Dmax-Dmin
x =———× 100 ……………( l)
D
Among them:
Dmax- maximum diameter, in millimeters (mm)
Dmin- minimum diameter, in millimeters (mm)
D—— Average maximum and minimum diameters, in millimeters (mm).
7.4 gloss
Compare the measured sample with the standard sample with a north sunlight or fluorescent lamp with a color temperature of 5500 K ~ 7200 K, pay attention to observe the reflection intensity, uniformity and image of the measured sample, and judge the gloss level.
7.5 Weld thickness
7.5. 1 comparison method
7.5. 1. 1 method principle
Using a group of standard samples with known bead thickness, the tested samples are compared with the standard samples, and the bead thickness grade is determined according to the texture of the tested samples.
7.5. 1.2 instruments and equipment
Standard sample of bead thickness, 10 times magnifying glass, gem microscope, strong light or optical fiber lamp.
7.5. 1.3 operation steps
Scrub the test sample clean.
Irradiate with strong light or optical fiber lamp, and compare the measured sample with the standard sample under 10 magnification magnifying glass or gem microscope to determine the bead thickness grade of the measured sample.
7.5.2 Direct measurement method (arbitration method)
6.5438+0 method principle
Put the cut sample under a measuring microscope and measure the thickness of the bead layer.
7.5.2.2 instrument
Measuring microscope.
7.5.2.3 operation steps
Cut the test sample from the middle, grind it flat, measure the thickness of nacre with a measuring microscope, at least measure the three maximum thicknesses and three minimum thicknesses of nacre, and take the average value to determine the thickness grade of nacre.
X-ray photography
Using a set of standard samples with known bead thickness, put the tested sample and the standard sample on the X-ray machine photographic table at the same time, take X-ray contrast photos, and compare and determine the bead thickness of the tested sample.
7.6 completion
After the tested sample is cleaned and dried, roll the tested sample, observe and record the type, quantity and distribution of surface defects of the tested sample with naked eyes, and determine the smoothness grade of the tested sample with reference to the standard sample.
7.7 Matching
Clean and dry the test sample and determine the matching level according to Table 8.
7.8 Classification requirements
Technical personnel engaged in grading cultured pearls should receive special skills training and master the correct operation methods. Two or three technicians independently complete the classification of the same test sample and obtain unified results. 8. 1 Basic content
The basic contents of the grading report or certificate shall include:
A) Name (seawater cultured pearls or freshwater cultured pearls shall be indicated)
B) the grade of cultured pearls in cultured pearls or ornaments
C) color
D) size
E) shape level
F) gloss
G) nacre thickness grade (except seedless cultured pearls)
H) smoothness
I) matching level (if involved)
J) Total mass (in grams, g).
8.2 Representation of quality factor level in grading reports, certificates and labels
8.2. 1 The quality factor grades in grading reports, certificates and labels can be expressed in Chinese and English codes.
8.2.2 When English codes are used to continuously express the level of quality factors, they shall be expressed in the order of shape, luster, smoothness, bead thickness (if involved) and matching degree (if involved).
Example 1: The quality factor level of mariculture pearl necklace is expressed in Chinese as:
Shape level: circle
Gloss: very strong
Finishing grade: flawless
Grade of weld thickness: medium.
Matching level: very good
Example 2: The English code of quality factor level of mariculture pearl necklace in Example 1 is:
A2AACA