全球寶石鑑定研習中心講師

林嵩暉 GIC 珠寶鑑定師資格證書，GIC 翡翠鑑定師證書              指導者: 林嵩山 台灣 GIC 創始人. 中華民國寶石協會理事長

Element Six 公司(戴比爾斯工業鑽石部門)生產的研究用CVD鑽石，左起 0.86克拉, 0.39克拉，0.50克拉

        天然粉紅鑽是很罕見的，因此發展出幾種處理方式能將粉紅色帶入天然鑽和高溫高壓合成鑽石中。其中一種廣泛應用的技術是藉由輻照和退火處理，將痕量的孤氮帶入N-V中心內（nitrogen-vacancy pairs : 鑽石中由氮與空穴結合產生的心）。N-V中心強烈吸收黃光和橙光，因此產生粉紅至紅的顏色。痕量孤氮需要經過處理，使其適當作用而自然發生於起始原料中，而能在合成過程中混入（Shigley等，2004年）；或者產自於天然鑽石經高溫高壓處理過程中，因其氮的缺陷而致分解的結果（Wang等，2005）。據波士頓的阿波羅鑽石公司研究，化學氣相沉積(CVD)生長的鑽石其N-V中心是獨一無二的，並且隨後發生的粉紅色可以在合成過程產生。

由阿波羅鑽石公司測試七個色彩鮮豔的CVD合成鑽石(顏色從Fancy Intense到Fancy Vivid pink或purplish pink)，本圖列舉3個

由阿波羅鑽石公司測試七個色彩鮮豔的CVD合成鑽石 ( 顏色從Fancy Intense到Fancy Vivid pink或purplish pink )，顏色相似於著名的澳洲天然粉紅鑽石礦區阿蓋爾(Argyle)。雕琢精良的刻面型CＶＤ合成鑽石，其大小介於0.28至0.67克拉之間，所有的樣本顏色均勻，大致上樣本乾淨，只包含少量針點狀包裹體。

天然鑽石和CVD鑽石的晶體形態學特徵

當長短波紫外線照射下，合成鑽石表現出強烈的橙紅色熒光。紅外光譜顯示的1344cm^-1微弱吸收峰是由不純的孤氮產生。此外，持續偵測到局部震動弱尖峰在1341，1355，1358，1363，1375，1379，1405（氫氣）和1450 cm^-1 （H1a）。觀察到一個有趣的特徵是中紅外光譜共存的尖銳吸收峰3107和3123 cm^-1。

阿波羅公司生產的CVD鑽石，左起1.70克拉，, 0.36克拉，0.21克拉

這兩者與氫有關，但3123 cm^-1吸收峰特別與CVD合成鑽石相關，而3107 cm^-1則普遍的存在於Ia型天然鑽石中。在所有的測試樣本中，3107cm^-1 吸收峰明顯強於3123 cm^-1吸收峰。這些紅外吸收峰也非常不同於先前報導過的白色，棕色，粉紅色的CVD鑽石（Martineau等，2004年；Wang等，2007）。

一顆由阿波羅鑽石公司生產的CVD鑽石原晶重0.189克拉

一顆由阿波羅鑽石公司生產的CVD鑽石原晶重0.189克拉

一顆由阿波羅鑽石公司生產的HPHT處理的CVD合成鑽石，重0.226克拉

一顆由阿波羅鑽石公司生產的高溫高壓(HPHT)處理的化學氣相沉積法(CVD)合成鑽石，重0.226克拉

CVD-Grown Pink Diamonds

    Natural pink diamonds are very rare. As a result, several treatments have been developed to introduce pink color into both natural and HPHT synthetic diamonds. One technique that is widely used to produce pink color involves the conversion of trace amounts of isolated nitrogen into N-V centers (nitrogen-vacancy pairs) through a combination of irradiation and annealing processes. N-V centers strongly absorb yellow and orange light, thus creating a pink to red color. The trace amounts of isolated nitrogen needed for the treatment to work properly can occur naturally in the starting materials, be incorporated during synthetic growth (Shigley et al., 2004), or be generated by disaggregation of other nitrogen-bearing defects in natural diamonds during high-pressure and high-temperature (HPHT) treatment (Wang et al., 2005). According to Apollo Diamond Inc. in Boston, CVD-grown diamond is unique in that N-V centers, and subsequent pink color, can be created during the synthesis process.

   Seven intensely colored CVD synthetic diamonds (graded as Fancy Intense to Fancy Vivid pink or purplish pink) were supplied by Apollo Diamond Inc. for this study. The colors were similar to the well-known natural pink diamonds from the Argyle mine in Australia. The faceted CVD synthetic diamonds ranged in size from 0.28 to 0.67 ct, with well-cut proportions. Color distribution was even in all of the samples. In general, the samples were clean, containing only a few pinpoint inclusions. When exposed to both long- and short-wave UV radiation, the synthetic diamonds displayed strong orange to red fluorescence. Infrared spectroscopy revealed very weak absorption peaks at 1344 cm-1 caused by the presence of isolated nitrogen impurities. In addition, weak and sharp peaks from local vibrations at 1341, 1355, 1358, 1363, 1375, 1379, 1405 (hydrogen), and 1450 cm-1 (H1a) were also consistently detected. An interesting feature observed in the mid-infrared spectra was the coexistence of sharp absorptions at 3107 and 3123 cm-1. Both features are hydrogen-related, but the absorption at 3123 cm-1 is specific to CVD synthetic diamonds, whereas the 3107 cm-1 peak is very common in natural type Ia diamonds. In all of the tested samples, the intensity of the 3107 cm-1 absorption was stronger than that of the 3123 cm-1 peak. These infrared absorption features are very different from those previously reported in white, brown, and pink CVD diamonds (Martineau et al., 2004; Wang et al., 2007).

     Spectral features observed from UV-Visible-NIR absorption spectroscopy strongly indicated that the pink CVD diamonds were colored mainly by the N-V centers with ZPL at 637.0 and 574.9 nm and their sidebands at the higher-energy side. GR1 (ZPL at 741.1 nm), the 595 center (594.2 nm), and ND1 (ZPL at 393.5 nm), all well-known irradiation-induced defects. The occurrence of Si-related absorptions (736.6/736.9 nm doublet) is a reliable identification feature in CVD synthetic diamonds.