1.1 该分类涵盖了商用天然白云母块云母的测定，旨在与云母的基本颜色或其来源无关。 1.2 白云母的特征是具有50到75°之间的光轴角（参见 附录X1 ); 当在600°C下加热5分钟时，重量损失不超过0.2 % （基于在120°C下干燥后的重量）。 1.3 本规范涵盖的天然白云母质量分类视觉系统基于可见外来夹杂物（如气泡、污点和斑点）的相对数量，以及波纹的相对数量和类型，以及其他物理性质。在这个系统中，一个完全清晰、透明、平坦的云母样品是完美的视觉标准。视觉缺陷数量的增加会降低视觉质量，本标准共涵盖13个级别的视觉质量。 这种分类方法通常被称为孟加拉邦-印度系统，纯粹是定性的，完全取决于个人意见和判断。 1.4 本分类中涵盖的视觉质量分类标准是各种质量及其相对位置的最佳商业概念。使用和应用这些标准的方法与本文中定义的方法不同，由买方指定，或由供应商和买方之间的协议定义。 1.5 标准尺寸分类是根据可用的矩形面积和工件将产生的矩形的最小尺寸来定义的。还描述了在进行厚度测量时应采取的预防措施。 1.6 本标准涵盖以下两种明确的商业制剂形式: 1.6.1 表1- 全切天然块状云母，0.007 在里面（0.178 mm）最小厚度。 1.6.2 表格2- 部分修整的天然块状云母，0.007英寸。最小厚度。 1.7 云母的基本颜色，如白色、红宝石色、浅绿、深绿色、棕绿色和朗姆酒，以及其他颜色，以及控制颜色的方法和与基本颜色相关的其他问题，不属于本分类的一部分。 1.8 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.9 部分 5. 在技术上与ISO 67-1981中规定的程序相同。 1.10 部分 6. 在程序上与ISO 5972-1978有所不同，但两者获得的数据应相同。 1.11 部分 7. 在技术上与ISO 2185-1972中规定的程序相同。 1.12 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本标准中包含的特性是控制视觉质量、可用面积、厚度、硬度和刚度所需的特性。

1.1 This classification covers the determination of commercially available natural muscovite block mica and is intended to be independent of the basic color of the mica or its source. 1.2 Muscovite mica is characterized by having an optical axial angle between 50 and 75° (see Appendix X1 ); and has a weight loss when heated for 5 min at 600°C not exceeding 0.2 % (based on the weight after drying at 120°C). 1.3 The visual system of classifying the quality of natural muscovite mica covered by this specification is based upon relative amounts of visible foreign inclusions such as air bubbles, stains, and spots in combination with relative amounts and types of waviness, as well as other physical properties. In this system, a perfectly clear, transparent, flat specimen of mica is the visual standard of perfection. Increasing amounts of visual defects lower the visual quality, and a total of 13 levels of visual quality are covered by this standard. This method of classification, generally known as the Bengal India System, is purely qualitative and is entirely dependent on personal opinion and judgment. 1.4 The standards for visual quality classification that are covered in this classification are the best commercially available concept of the various qualities and their relative positions. Variations in the methods of using and applying these standards from those herein defined are specified by the purchaser, or defined by agreement between the supplier and the purchaser. 1.5 Standard size classifications are defined, based upon available usable rectangular areas and the minimum dimensions of the rectangles that the pieces will yield. Precautions to be taken in making thickness measurements are also described. 1.6 This standard covers the following two definite forms of commercial preparation: 1.6.1 Form 1— Full-trimmed natural block mica, 0.007 in. (0.178 mm) minimum thickness. 1.6.2 Form 2— Partially-trimmed natural block mica, 0.007 in. minimum thickness. 1.7 The basic color of mica, such as white, ruby, light green, dark green, brownish green, and rum, as well as other colors, and the method of controlling the color and other problems associated with the basic color, are not a part of this classification. 1.8 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.9 Section 5 is technically identical to procedures specified in ISO 67-1981. 1.10 Section 6 differs somewhat in procedure from ISO 5972-1978, but data obtained by either is expected to be identical. 1.11 Section 7 is technically identical to procedures specified in ISO 2185-1972. 1.12 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The properties included in this standard are those required to control the visual quality, usable area, thickness, hardness, and stiffness.