What is the HPHT process?
HPHT Treatment. High Pressure High Temperature Diamond Color Treatment (HPHT) High pressure high temperature color treatment is the process of working with a diamond color that you have, and then PERMANENTLY changing it to a new color. Usually more vibrant.
What does the GIA say about HPHT treatment?
Diamonds were first synthesized from graphite in the 1950s by the HPHT process. In the mid-1980s, the process was modified to create diamond film. Later, chemical vapor disposition (CVD) improved diamond film production. In the mid-1990s, diamond-like coatings (DLC) improved on CVD, requiring less temperature and less energy.
What is an HPHT well?
The colour of a diamond following HPHT- treatment is dependent on the exact conditions used and the diamond type. The HPHT process is perfectly acceptable so long as it is disclosed to the purchaser. Scientists divide diamonds into various types. The vast majority (over 97%) of diamonds handled by the jewellery industry are called Type I.
What is HPHT diamonds?
HPHT enhancement improves the diamond at the atomic level, improving color inducing bonds and results in a stronger, more perfect diamond after the process and often, D or E color. Nothing is added to the diamond and the process is permanent and native to the diamond itself. Pros of HPHT enhanced Diamonds: 1 - Stronger than an untreated diamond. *All* diamonds …
Is HPHT treatment permanent?
The high pressure and 2300 degrees Celsius mimic the temperature at the Earth's core and is a non-invasive, permanent process so that the beautiful results will last.Mar 18, 2019
How does Hpht work?
The HPHT process involves the careful positioning of a diamond by a highly trained gemologist into a "containment cube" that is surrounded by heating mechanisms. The cube is then placed in a press to apply the same amount of pressure that the earth creates when forming diamonds.
Is Hpht natural diamond?
Non-HPHT diamonds and HPHT diamonds are both real, natural diamonds. The difference is in the treatment. Because an HPHT diamond has been treated by extreme heat and pressure, its color has been enhanced and improved.
What is Hpht?
What is HPHT? ( High Pressure, High Temperature) HPHT or High Pressure, High Temperature is defined as those Wells with a bottom hole temperature greater than 150°C (300°F) and requiring pressure control equipment with a rated working pressure of above 69 MPa (10,000psi) (S.P.E E&P Glossary, HPHT, 2013).
Do HPHT diamonds hold value?
How does the HPHT process affect the resell value of a diamond? An HPHT processed diamond will be worth significantly less than an untreated diamond of the same color/clarity combination, but will still increase in value at the same rate.
Which is better HPHT or CVD?
HPHT is a great way to enhance any diamond's clarity and colour (sometimes natural diamonds undergo this process as well!) and we find that CVD diamonds that have been finished in this way look better and brighter than gemstones that have undergone CVD alone.Nov 9, 2021
Are HPHT diamonds magnetic?
A total of 104 synthetic diamonds from nine different manufacturing sources were tested. Of the HPHT-grown synthetic samples tested, 58% registered a detectable magnetic response. Strong N52-grade neodymium magnets were able to detect 35% more HPHT synthetics than traditional ferrite and alnico magnets.
What does HPHT diamond mean?
high pressure, high temperatureHPHT stands for high pressure, high temperature and is one of the primary methods used to grow diamonds in a lab. This diamond growth process subjects carbon to extreme temperatures and pressures and is meant to replicate the extreme heat and pressure conditions deep within the earth where natural diamonds form.Jul 25, 2016
Are HPHT diamonds moissanite?
HPHT stands for high pressure and high temperature. Unlike diamond simulants such as cubic zirconia, moissanite, and white sapphire, HPHT diamonds are real diamonds.
Early Responses to HPHT Diamond Treatments
Initially, no laboratory tests could identify HPHT diamond treatments. In response to concerns in the jewelry trade, GE agreed to mark the girdle facet of their treated diamonds with the inscription “GE POL.”
A Brief History of Synthetic HPHT Diamonds
Diamonds were first synthesized from graphite in the 1950s by the HPHT process. In the mid-1980s, the process was modified to create diamond film. Later, chemical vapor disposition (CVD) improved diamond film production.
How does HPHT work?
The HPHT Diamond Growth Process 1 Diamond seed is placed in a specifically designed press. 2 The growth chamber is heated to 1300-1600 °C with pressures above 870,000 pounds per square inch. 3 The molten metal dissolves the high purity carbon source. 4 Carbon atoms precipitate on a small diamond seed crystal, and a synthetic diamond begins to grow. 5 The lab-grown crystal is then cut and polished by a diamond cutter.
What is HPHT in diamonds?
HPHT stands for high pressure, high temperature and is one of the primary methods used to grow diamonds in a lab. This diamond growth process subjects carbon to extreme temperatures and pressures and is meant to replicate the extreme heat and pressure conditions deep within the earth where natural diamonds form.
Why is proper identification important?
Because they differ greatly in commercial value, proper identification is vital for both valuation and disclosure to consumers at point of sale. In some cases, a trained gemologist can recognize these CVD/HPHT grown and treated diamonds by using standard gem-testing equipment.
Where are synthetic diamonds grown?
Synthetic diamonds are grown in several countries for both jewelry and industrial purposes — with industrial use being the primary function of the material ( Large Colorless HPHT Synthetic Gem Diamonds from China, Gem News International, Gems & Gemology, Spring 2016, Vol. 52, No. 1).
What is the starting material for diamonds?
Within the capsule, a carbon starting material, such as graphite, dissolves in a molten flux consisting of metals such as iron (Fe), nickel (Ni) or cobalt (Co), which lowers the temperature and pressure needed for diamond growth.
How to work under HPHT conditions?
Working under HPHT conditions requires specialized equipment, proper tools and training. Advanced planning is an important aspect of successful operations; modified operational procedures must often be employed to address HPHT concerns. Whereas mistakes made in conventional wells may create routine lost time, preventing disastrous consequences to equipment and personnel from HPHT operations requires exceptional diligence. The long history of developing tools to effectively tame HPHT conditions and the experience dealing with these conditions continue to enable the oil and gas industry to push the boundaries to deeper depths and in hotter wells in the ongoing search for new sources of hydrocarbons.
What is HPHT well?
The designation of high-pressure, high-temperature is given to wells that present extreme conditions to operators and service companies. The term HPHT may be applied to wells that have only high pressure or high temperature—few wells have both characteristics—but regardless of the designation, HPHT wells offer specific challenges ...
What is pore pressure?
Pore pressure follows a pressure gradient—the rate of increase in pore pressure versus depth that can change rapidly across geologic features. To prevent formation fluids from entering a wellbore while drilling, engineers use weighted drilling fluid.
How deep is a well?
To reach the HPHT threshold of 350°F (vertical green line) and Earth's average geothermal gradient of 1.4°F/100 ft (red line), a well would have a depth of almost 20,000 ft [6,100 m] (horizontal green line).
How deep should geothermal wells be?
The Earth's geothermal gradient averages about 1.4°F/100 ft [2.55°C/100 m]. At this average gradient, the 350°F threshold would require a well depth in excess of 19,700 ft [6,000 m] (Figure 3). Downhole temperatures, however, are often affected by natural conditions or external influences. Proximity to localized geothermal hotspots can quickly raise downhole temperatures encountered while drilling. At very shallow depths, steam injection used to help produce heavy oil can greatly increase downhole temperatures. Wells drilled in deep and ultradeep waters often have geothermal gradients that are lower than that of the Earth's average. Consequently, deepwater wells often have high pressure and temperatures that are below the HT threshold.
How many wells were drilled in 2012?
An oil industry study estimated that of the more than 100,000 wells drilled worldwide in 2012, about 1.5% should be classified as HPHT. Although relatively small in number, these wells often represent significant resource potential and are often located in areas where exploration in new horizons is ongoing.
What is the chemical used to alter / reduce a component of, or the entire color, of a por
Bleaching. – a chemical used to alter / reduce a component of, or the entire color, of a porous gem. Some gemstones are bleached and then dyed, a form of “combination treatment.”. 1. The most commonly encountered bleached gems include:
What is the second step of gem treatment?
This is sometimes followed by a heat treatment to further modify the color. This second step also known as a “combination treatment .
What is the Federal Trade Commission?
In the United States, the Federal Trade Commission has established a set of consumer guidelines outlining the need for treatment disclosures and special care requirements, and countries around the world either adhere to similar guidelines, or have regulations of their own.
What is surface coating?
– altering a gem’s appearance by applying a coloring agent like paint to the back surfaces of gems (a treatment known as “backing”), or paint applied as a coating to all or a portion of a gemstone’s surface with the effect of altering the color . 1.
What is a cavity filling?
– filling surface-reaching fractures or cavities with a glass, resin, wax or oil to conceal their visibility and to improve the apparent clarity of gem materials, appearance, stability, or in extreme cases—to add to a slight amount of weight to a gem.
What color is tanzanite?
Tanzanite – Though rarely used, tanzanites have been coated to improve the intensity of their blue-violet color. Classic tanzanite exhibits a deep, purplish blue color (left). Pale tanzanite, and other pale stone species are sometimes coated with an ink-like substance to try to deepen and improve their color (right).
