13
2023
-
07
How to distinguish CVD synthetic diamonds from HTHP synthetic diamonds
Author:
HPTP diamonds and CVD diamonds are two methods for producing synthetic diamonds; the resulting man-made diamonds do not have identical physical and chemical properties, and they exhibit subtle differences in certain respects.
How to distinguish CVD synthetic diamonds from HTHP synthetic diamonds
HPT‑grown diamonds and CVD diamonds are two methods for producing synthetic diamonds; the resulting gemstones do not exhibit identical physical and chemical properties, and subtle differences persist in certain respects.
1. In terms of color, HPHT‑grown diamonds are predominantly yellow and brownish‑yellow, with fewer colorless or blue stones, whereas CVD‑grown diamonds are mostly brownish‑tinted, though some are also colorless or blue.
2. In terms of crystal structure, HPHT‑grown diamonds typically occur as octahedral–cubic polyhedral aggregates; their crystals are well‑formed and often exhibit irregular dendritic growth patterns, whereas CVD‑grown diamonds are predominantly tabular or thick‑tabular in habit.
3. On the color zoning, HPHT synthetic diamonds generally exhibit uneven coloration; yellow synthetic diamonds often display hourglass‑shaped or Maltese cross‑shaped color zoning.
4. In terms of internal characteristics, HPHT‑grown diamonds typically contain needle‑like, dust‑like, crumb‑like, and various irregularly shaped metallic inclusions. By contrast, CVD‑grown diamonds generally exhibit fewer inclusions; only occasional needle‑like features, black amorphous carbon particles, or graphite are observed.
5. Under a polarizing microscope, HPHT‑grown diamonds exhibit very weak dichroism and display faint black cross‑shaped bright bands, with barely perceptible changes in interference colors, whereas MPCVD‑grown diamonds show more pronounced extinction and resemble natural diamonds more closely.
6. In fluorescence and phosphorescence detection, HPHT‑grown diamonds typically exhibit yellow‑green fluorescence under shortwave (SW) UV, with SW > LW; in contrast, CVD diamonds generally show more variable responses under both longwave (LW) and shortwave (SW) UV, ranging from inert to orange fluorescence.
Accordingly, given these distinct characteristics, different methods can be employed to identify synthetic diamonds. HTHP and CVD diamonds exhibit distinct fluorescence signatures, allowing for their differentiation by analyzing the intensity and color of their fluorescence signals.
The crystal structures of HTHP diamonds and CVD diamonds are not identical, so they can also be distinguished using X-ray diffraction patterns. Additionally, Raman spectroscopy can be employed to differentiate between these two types of diamonds; their Raman spectra exhibit distinct features, allowing for their identification through spectral analysis.
Synthetic diamond
Related News
On February 28, the unveiling ceremony of Henan Fengyouchuang Materials Technology Co., Ltd. (hereinafter referred to as Henan Fengyouchuang), a joint venture established by Shenzhen Uniplasma and Huanghe Xuanfeng, was solemnly held in Xuchang. Attending the ceremony were Yang Zengjun, Party Secretary and Chairman of the Xuchang Municipal Investment Group; Quan Feng, Chairman of Shenzhen Uniplasma; Chai Bohao, Deputy General Manager of Shenzhen Uniplasma; Du Ping, Deputy Director of the Henan Branch of the China Development Bank; Li Ge, Chairman of Huanghe Xuanfeng; Pang Wenlong, General Manager of Huanghe Xuanfeng, along with other leaders.
On April 16–17, the 2026 (Second) Future Semiconductor Industry Innovation Conference was grandly held at Yinsan Lake in Suzhou.
On March 18–19, the 2026 Second Symposium on Fourth-Generation Semiconductor Technology was grandly held in Hangzhou. As a leading enterprise in China’s MPCVD equipment and diamond materials sectors, Uniplasma showcased its core products and technical solutions at the conference, engaging in in-depth exchanges with industry peers and jointly discussing the future of the sector.
New Materials, New Future | Uniplasma showcases at the Carbontech 2025 Carbon Materials Exhibition
On December 11, the 9th International Carbon Materials Conference and Industry Exhibition, Carbontech 2025, concluded successfully at the Shanghai New International Expo Center. At the event, Uniplasma made a prominent appearance with its core technologies and products, bringing together industry peers to discuss new directions and a promising future for the diamond industry.
On November 16, the 27th China Hi-Tech Fair and the Asia Semiconductor and Integrated Circuit Industry Exhibition concluded successfully at the Shenzhen (Bao’an) International Convention and Exhibition Center. At the event, Uniplasma showcased its MPCVD equipment and diamond material products, offering a “core” solution to address the semiconductor industry’s “thermal management crisis” and injecting “core” momentum.
From October 15 to 17, the 2025 Bay Area Semiconductor Industry Ecosystem Expo was grandly held at the Shenzhen (Futian) Convention and Exhibition Center. Uniplasma showcased diamond films, thermal‑sink diamonds, optical diamonds, boron‑doped diamonds (BDD), and MPCVD equipment, comprehensively demonstrating the company’s semiconductor thermal‑management solutions based on diamond materials as well as its technological prowess in MPCVD equipment.
On September 17, Uniplasma and Huanghe Xuanfeng jointly established a joint venture—Henan Fengyouchuang Materials Technology Co., Ltd. (hereinafter referred to as Henan Fengyouchuang). This collaboration not only represents an efficient synergy between “cutting-edge technology” and an “industrial flagship,” but will also seamlessly close the entire industrial chain—from “equipment R&D” and “material growth” to “large-scale application”—marking a major leap from technological leadership to market leadership. Uniplasma Chairman Quan Feng, Huanghe Xuanfeng Chairman Li Ge, Vice Chairman and General Manager Pang Wenlong, and others attended the signing ceremony.
Adhesion Strength Testing of Diamond Films on Silicon Carbide Substrates
Diamond films, owing to their exceptional hardness, thermal conductivity, and chemical stability, are often bonded to silicon carbide substrates to form composite functional materials. The interfacial bonding strength between the two directly determines the service life of the composite under real‑world operating conditions, and the methods for its measurement as well as the interpretation of the results carry significant engineering implications.
Follow us
Follow the public account
Tel：
Email：
在线客服添加返回顶部
右侧在线客服样式 1,2,3 3
图片alt标题设置： Shenzhen Uniplasma Technology Co., Ltd.
表单验证提示文本： Content cannot be empty!
循环体没有内容时： Sorry, no matching items were found.
CSS / JS 文件放置地