Calcite crystals in many cases are Employed in optical tools, and even the graphite in pencil direct are sheets of crystals that in essence crack apart layer by layer to put in writing. Silica can sort silicate crystals which might be The premise for quartz, mica, olivine, and many other crystals and minerals.
杂质、裂纹越少越好。质地好的水晶制品，应看不到星点状、云雾状和絮状分布的气液包裹体或组成玉石的颗粒。有裂纹、斑点，则属于次品。
人造水晶分为熔炼水晶与养殖晶：据水晶专家汪毅的阐述，随着水晶的价值提高，喜欢的人增多，水晶也引起了作伪者的兴趣，现阶段中国水晶市场常见的造假方法为：
Tetragonal: These crystals kind prisms and double pyramids. The construction is sort of a cubic crystal, other than 1 axis is longer than another.
25If you are a Billy Crystal lover, you are going to love this movie.如果你是比利·克里斯特尔的影迷，你就会喜欢这部电影。《柯林斯英汉双解大词典》
第二种是“半包裹体”，在水晶结晶以后，由于受到地球引力的影响而产生的裂隙，晶体外的一些物质通过水晶的裂隙渗透到水晶内部，一部分包裹于水晶之中另一部分露于水晶之外。我们可以看到物质渗进水晶的裂迹，常被称为“通道”，这种包裹体所形成的景象相对地较受自然环境和时间的影响，相应的价值也比较�?。
水晶与高档宝石的净度要求有很大不同。高档宝石稀少罕见，所以一般人们普遍对高档宝石的净度不会过于苛求。而水晶的产量着实大得惊人，所以通常人们会要求水晶净度越高越好，尽量避免有较明显的内含物的水晶。
②固体包裹体：指呈固态相存在包裹体，多因岩浆、热液、变质作用等形成的早期结晶物被水晶捕获而形成。
24I want to make my indicating crystal apparent.我想把我的意思解释得清清楚楚。《牛津词典》
多色�?无色水晶没有多色性。有色水晶有弱到强的多色�?表现为体色的不同深浅。
say cheese something that a person who is having a photograph of you tells you to state so that your more info mouth can make The form of a smile
Molecular Crystals: Overall molecules are bonded to each other within an arranged fashion. A superb illustration is often a sugar crystal, which includes sucrose molecules.
《古今小说·李公子救蛇获称心》：“器皿皆是玻璃、水晶、琥珀、玛瑙为之，曲尽巧妙，非人间所有。”
Tetragonal �?Characterised by 3 mutually perpendicular axes, two of which happen to be equivalent in duration, when the 3rd is for a longer period or shorter and perpendicular to one other two.