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This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This document replaces GB/T 28796-2012 Craft crystal decoration. In addition to structural adjustments and editorial changes, the following main technical changes have been made with respect to GB/T 28796-2012:
a) “Product classification” and “Quartz glass” are deleted from “1 Scope” (see Clause 1; Clause 1 in Edition 2012);
b) "GB/T 16552 Gems - Nomenclature and "GB/T 7962.12 Test methods of colorless optical glass - Part 12: Spectral internal transmittance" are deleted from "2 Normative references" (see Clause 2; Clause 2 in Edition 2012);
c) some of the terms and definitions involved hereof are modified (see 3.1, 3.2, 3.3, and 3.4; 3.1, 3.2, 3.3.3, 3.4 and 3.5 in Edition 2012);
d) “Classification” is deleted (see Clause 4 in Edition 2012);
e) the graduation indexes are deleted from the requirements and only the minimum quality requirements are specified (see 4.1, 4.2 and 4.3; 5.1, 5.2 and 5.3 in Edition 2012);
f) “Test method II” for surface roughness is deleted (see 6.2.1.3 in Edition 2012);
g) the test method for transmittance is modified (see 5.2.2.1, 5.2.2.2 and 5.2.2.3; 6.2.2 in Edition 2012);
h) the test method for limit of harmful substance is modified (see 5.5; 6.5 in Edition 2012);
i) the sampling rules are modified and the provision of "1% of sampling rate" (see 7.1.2 in Edition 2012);
j) the item "surface roughness" is deleted from the end-of-manufacturing inspection (see 6.1.3; 7.1.3 in Edition 2012);
k) the classification of type inspection items is added (see 6.2.4);
l) the judgment rules are modified (see 6.3; 7.3 in Edition 2012).
This standard was proposed by China National Light Industry Council.
This document is under the jurisdiction of SAC/TC 377 National Technical Committee on Glass of Standardization Administration of China.
The previous editions of this standard are as follows:
——it was firstly issued as GB/T 28796-2012 in 2012;
——this edition is the first revision.
Craft crystal decoration
1 Scope
This document specifies the terms and definitions, requirements, test methods, inspection rules, and marking, packaging, transportation and storage for craft crystal decoration.
This document is applicable to craft crystal decoration made of mainly synthetic quartz, crystal glass and rock crystal (hereinafter referred to as the decoration).
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 7962.1 Test methods of colourless optical glass - Part 1: Refractive index and coefficient of dispersion
GB 28480 Adornment - Provision for limit of baneful elements
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
craft crystal decoration
artworks, handicrafts, ornaments and articles of everyday use made of mainly synthetic quartz, crystal glass and rock crystal by mechanical and manual processing such as thermoforming, cutting, grinding and polishing and assembly
3.2
synthetic quartz
crystal formed mainly of silica as the main raw material under artificial conditions, with a crystal structure similar to that of rock crystal, uniform color and few crystal defects
3.3
crystal glass
glass with high transparency, good surface gloss and crystal clearness, presenting good light and color characteristics, made by mechanical or manual processing such as thermoforming, cutting, grinding and polishing, used to manufacture high-grade utensils, artworks and ornaments
3.4
rock crystal
crystalline mineral formed of mainly silica under specific natural conditions, which is mostly colorless and transparent, purple, dark brown, green, etc., and most of which contain hair-like crystals, bubbles, impurities and crystalline cloud matter
4 Requirements
4.1 Appearance quality
Appearance quality shall comply with the provisions in Table 1.
Table 1
Item Index
Processability Overall appearance There shall be no fracture, crack, worn-out and impurity; no obvious trace on the bonding part; highly three-dimensional
Carved lines Clear lines, distinct layers, no burrs
Appearance properties Bubble diameter/mm ≤ 0.4
Allowed number of visible bubbles
pcs/100cm3 4.0
Color uniformity Uniform color
Note: synthetic quartz, rock crystal and foaming materials only have their processability evaluated.
4.2 Physical properties
The physical properties of fine grinded and polished ornaments shall comply with the provisions in Table 2.
Table 2
Item Index
Color stability No discoloration after irradiation for 8h
Surface roughness/μm ≤ 0.5
Transmissivity/% ≥ 90.0
Refractivity (nd) ≥ 1.47
Note: transmittance and refractivity are only applicable to colorless transparent glass.
4.3 Dimensional tolerances
Dimensional tolerances shall comply with the provisions in Table 3, and special products shall meet the contract requirements.
Table 3
Item Deviation
%
Product shape Specification
Spherical, diameter A≤50mm ±3.0
50mm80mm ±4.0
Other shapes — ±4.0
Note: A represents the design size of the product.
4.4 Assembling requirements
The shape and position shall conform to the design drawing, and the adhesion shall be firm and secure.
4.5 Limit of harmful substances
The content of lead and cadmium in an ornament shall meet the requirements for limit of baneful elements - lead and cadmium in GB 28480.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Inspection rules
7 Marking, packaging, transportation and storage
