包括浅棕色、深棕色、灰棕色“烟水晶”和称为黑晶的黑色变种。受到辐射时，无色石英会变成灰棕色。褐色石英产状呈六方棱柱，具金字塔形末端，其中有些矿物有金红石内含物。
弧形墙处那些黄褐色的壁纸已经被剥去；曾经的咖啡桌子也被一个石英胡桃木桌子所取代，奥巴马强调，这样水杯将不会在桌子上再留下任何污点。
The curved walls now had striped tan wallpaper, and the coffee table had been replaced by a walnut-and-mica table that, Obama noted, would resist stains from water glasses.
石英没有纯的黄宝石明亮夺目，但是产量比较丰富。大多数是由各种各样的紫水晶加热转变成褐色的。
The quartz is much less brilliant and more plentiful than true topaz. Most of it is a variety of amethyst that heat has turned brown.
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