鑽石的血型Ia、Ib、IIa、IIb

edit by Judy Tu

鑽石就像人一樣，分成幾種血型，有Ia、Ib、IIa、IIb，後來連AB型都出現了。由於某些血型比較稀少，物以稀為貴，自然要多一番介紹，成為注目收藏的選標之一。大、美、稀少，國際的寶石證書多會鎮重介紹多一份附錄以示份量。此以拍賣會上的一顆粉鑽為例，將拙譯放於此做為參考。

GIA彩色鑽石分級證書的鑽石類型分類 #.........

科學家基於氮的存在與否將鑽石分為兩種主要”類型” — I 型和 II 型，氮可以佔替鑽石原子結構中碳原子的位子。這兩種鑽石類型可以根據其化學和物理特性的差異進行區分。幾乎不含氮的II型鑽石再被分為兩類（IIa和IIb），這兩類都相當少見，不到所有寶石級鑽石的2%。

根據GIA實驗室的分析記錄，編號＃……… GIA彩色鑽石分級證書中所描述10.10克拉之橢圓明亮型鑽石，鑑定確定為IIa型粉紅色鑽石。IIa型粉紅色鑽石在自然界中非常罕見，通常有相對較少的內含物，並因其原石大部分呈均勻的顏色而被注目。與許多其他彩色鑽石不同的，粉紅鑽石的顏色不僅可能由蘊含物造成，亦可能是鑽石被運送到地殼過程中處於熱和壓力的結果。IIa型粉紅鑽石在世界各地數個礦區被發現。歷史上，它們首被發現於印度（特別是戈爾康達地區），在更近時期的著名產區來自巴西和非洲。

在著名的寶石級鑽石中，70.39 克拉的皇后玫瑰Empress Rose和 28.15克拉的阿格拉Agra皆為IIa型粉紅彩鑽的例證。

Diamond type classification for GIA colored Diamond Grading Report #..........

Scientists classify diamonds into two main "types"- type I and type II - based on the presence or absence of nitrogen which can replace carbon atoms in a diamonds atomic structure. These two diamond types can be distinguished on the basis of differences in their chemical and physical properties. Type II diamonds contain little if any nitrogen and they are subdivided into two groups (IIa and IIb) both of which are quite rare less than 2% of all gem diamonds).

According to the records of the GIA Laboratory, the 10.03 carat Oval Modified Brilliant diamond described in GIA Colored Diamond Grading Report #........... has been determined to be a type IIa pink diamond. Type IIa pink diamonds are very rare in nature, often have relatively few inclusions and are noted for their mostly homogenous color in the rough. Unlike many other colored diamond, the color in pink diamonds can not only be caused by impurities, but it may also be a result of the diamond exposure to heat and pressure during transportation into the earth’s crust. Type IIa pinks have been found in a number of mining regions around the world. Historically they were found in India (particularly from the Golconda region) and, in more recent times, most notably from Brazil and Africa.

Among famous gem diamonds, the 70.39 carat Empress Rose and the 28.15 carat Agra are examples of type IIa pinks.