Topaz
黃玉
Topaz is a hard, transparent mineral. It is a compound of aluminum, silica, and fluorine.
黃玉是一種堅硬、透明的礦物質。它是鋁、硅和氟的化合物。
Gem topaz is valuable. Jewelers call this variety of the stone “precious topaz”. The best-known precious topaz gems range in color from rich yellow to light brown or pinkish red. Topaz is one of the hardest gem minerals. In the mineral table of hardness, it has a rating of 8, which means that a knife cannot cut it, and that topaz will scratch quartz.
寶石級黃玉價值不菲。珠寶商把這種石頭稱為“貴黃玉”。最出名的貴黃玉有各種顏色，如深黃色、淡棕色、淺紅色等。黃玉是最堅硬的寶石礦中的一種。在礦石硬度表上，它的硬度為8，這表明刀子不能割開它而它可在石英上劃痕。
The golden variety of precious topaz is quite uncommon. Most of the world’s topaz is white or blue. The white and blue crystals of topaz are large, often weighing thousands of carats. For this reason, the value of topaz does not depend so much on its size as it does with diamonds and many other precious stones, where the value increases about four times with each doubling of weight. The value of a topaz is largely determined by its quality. But color is also important: blue topaz, for instance, is often irradiated to deepen and improve its color.
金色的貴黃玉品種非常罕見。世界上大多數的黃玉是白色或藍色的。這些白色或藍色的黃玉晶體很大，常常有數千克拉重。由于這個原因，黃玉的價值不像鉆石和許多其它寶石那樣主要依賴于其大小，重量翻一番價值即上升約四倍。黃玉的價值很大程度上取決于其品質，但顏色也很重要。舉例來說，藍色的黃玉常需放射處理以加深和改善其顏色。
Blue topaz is often sold as aquamarine and a variety of brown quartz is widely sold as topaz. The quartz is much less brilliant and more plentiful than true topaz. Most of it is variety of amethyst: that heat has turned brown.
藍色的黃玉常被作為海藍寶出售，許多種棕色石英則被當作黃玉廣為販賣。石英光亮度遠小于黃玉，礦藏儲量也遠較黃玉豐富。大多數石英是一種紫水晶，高溫使其變?yōu)樽厣?
注：黃玉，礦物學家也稱之為黃晶，英文名Topaz，國內珠寶界常稱之為托帕石，為英文的音譯。這主要是因為無論是黃玉還是黃晶，都會和我國珠寶界原有的一些寶石的稱呼相混淆。在我國，黃色的和田玉（軟玉）長期被稱為黃玉，尤其是在考古界；而黃晶又和水晶中的黃水晶容易相混。（來源：百度百科）
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