2016年7月25日 · With the traditional diamond growth method, called high-pressure, high-temperature (HPHT), synthetic diamonds are produced from carbon material in apparatuses that mimic the high pressure, high temperature conditions of natural diamond formation in the earth.

2016年11月7日 · Summarizes statistical data and distinctive features of several thousand gem-quality HPHT synthetic diamonds examined by GIA from 2007 through 2016.

New Diamond Technology’s colorless HPHT-grown synthetic diamonds are being faceted into gems for the jewelry trade. This study of 44 representative samples revealed that the company can create faceted colorless and faintly colored synthetics weighing up to …

2018年8月9日 · There are two types of high-pressure, high-temperature processes related to diamond: HPHT treatment and HPHT diamond growth. HPHT laboratory-grown diamonds were developed in the mid-1950s, with the first gem-quality production in the early 1970s and extensive production beginning in the 1990s.

HPHT synthetics are making inroads into the large diamond market, with cut stones larger than 10 carats, as well as the colorless melee market, where small HPHT synthetics are being mass-produced in China.

The gemological and spectroscopic properties of 52 colorless to fancy light-colored HPHT synthetic diamonds (40 of them colorless or near-colorless) produced by AOTC using either toroid- or BARS-press technologies were characterized.

2017年11月8日 · The Carlsbad laboratory recently examined an HPHT synthetic diamond that is now the largest faceted lab-grown diamond examined by GIA. The specimen was a cushion modified brilliant weighing 15.32 ct, with grades equivalent to I 1 clarity and H color (figure 1).

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gem-quality synthetic diamonds, where near-color-less specimens are more challenging to produce. Most synthetic diamonds used for jewelry are pro-duced by either high-pressure, high-temperature (HPHT) or chemical vapor deposition (CVD) tech-niques.AdvancesinCVDtechnologies,aswellasan …

2024年12月2日 · There has since been a sharp decline in submissions of yellow-orange HPHT-grown diamonds, with colorless samples now representing the vast majority of submissions. In the years 2021–2023, more than 90% of HPHT-grown diamond intake was colorless—a trend that likely reflects consumer preferences.