HPHT Cubic Press Machine

By Alex Klimchenko · Updated November 2, 2026

Labrilliante does not sell HPHT equipment. Here is how an HPHT cubic press is built, and how the lab-grown diamonds it grows differ from CVD.

Labrilliante is a US-based manufacturer and wholesale supplier of lab-grown diamonds (HPHT & CVD), serving jewelry retailers and brands since 2017. If you searched for an HPHT machine or an HPHT diamond machine, this page explains how lab-grown diamonds are made by HPHT, using GIA's published description of the process and a US patent on press design.

HPHT stands for high pressure, high temperature. GIA lists it as one of the primary methods for growing lab-grown diamonds. A diamond machine of this kind is an HPHT press: a diamond seed is placed in a specifically designed press, and growth takes place in a small capsule inside an apparatus capable of generating very high pressures.

GIA's 4Cs site explains the idea. HPHT recreates part of the conditions under which a diamond forms: pressure and temperature. The result has the same crystal structure as natural diamonds and nearly the same properties, and GIA issues a Laboratory-Grown Diamond Report for it.

A US patent (US 8,851,871, published October 2014) describes belt, tetrahedral and cubic designs as known designs for high pressure presses. This page covers the cubic press, the design in its title. The patent gives no pressure or temperature figures, so none are attributed to any single design here.

In the cubic design described in the patent, the anvils meet on a cube: the engagement surfaces of the anvils converge upon a defined cube-shaped volume. Six press bases would be arranged so that their anvils converge on the reaction cell, and pressure is applied substantially equally on each side of it. The square anvil surfaces apply pressure and heat to the cell. That is the construction; the patent says nothing about growth conditions.

The conditions come from GIA and describe HPHT growth in general. GIA does not name the press type. Per GIA, the growth chamber is heated to 1300-1600 °C, with pressures above 870,000 pounds per square inch. GIA's page does not describe press construction, so the six-anvil geometry above comes from the patent, and the temperature and pressure from GIA.

CVD takes a different route. GIA says CVD stands for chemical vapor deposition and is another method used for making lab-grown diamonds. The diamonds grow from a hydrocarbon gas mixture at moderate pressures and temperatures in a vacuum chamber.

Both methods produce lab-grown diamonds. For a retailer, the method says how a stone was grown, not how good it is. Color, clarity, cut and carat weight are read from the report or the stone itself.

GIA notes that HPHT-grown crystals typically show cubic faces in addition to octahedral ones.

Color can also change after growth. GIA relates pink and red colors in HPHT crystals to post-growth treatment with radiation and heat, and says the color of brown CVD material can be removed by heat treatment prior to faceting. If a customer asks why a colored lab-grown diamond looks the way it does, the answer may include a treatment step, and the report is the document to ask about.

GIA also states that identifying markers allow its scientists to determine which method was used to grow a lab-grown diamond. That is laboratory work, not something a buyer does at the counter. If the growth method matters for your customer, ask us what we can tell you about a specific stone.

We supply lab-grown diamonds grown by HPHT and CVD. IGI- and GIA-certified lab-grown diamonds are available, plus calibrated melee (reports on request), colored lab-grown diamonds and custom cuts. We have 100,000+ loose lab-grown diamonds in stock.

Not every stone has a report. Certified and non-certified stones are both in stock, and the non-certified ones are mostly under 1 ct. If you need a report for a specific stone, ask us which stones come with one.

Looking for equipment? We do not sell HPHT equipment. Looking for lab-grown diamonds? Browse loose stones at labrilliante.com/diamonds/lab-diamonds, or read about supply on the wholesale lab-grown diamonds page. To ask about lab-grown diamonds, write to info@labrilliante.com or call +1 551-321-8771 with the shapes, sizes and reports you need, and we will say what is available.

Do you sell HPHT machines or cubic presses?

No. Labrilliante does not sell HPHT equipment. We supply lab-grown diamonds to jewelry retailers and brands.

What does HPHT stand for in lab-grown diamonds?

HPHT stands for high pressure, high temperature. GIA describes it as one of the primary methods used to grow lab-grown diamonds. A diamond seed is placed in a specifically designed press, and growth happens in a small capsule inside an apparatus that can generate very high pressures.

How does a cubic press machine work?

In the cubic design described in a US patent (US 8,851,871), six press bases would be arranged so that their anvils converge on a cube-shaped reaction cell, with pressure applied substantially equally on each side. Separately, GIA gives the conditions for HPHT growth in general, without naming a press type: 1300-1600 °C and pressures above 870,000 pounds per square inch.

Is HPHT different from CVD?

Yes, in how the lab-grown diamond grows. HPHT uses a seed in a capsule under very high pressure and heat. CVD grows lab-grown diamonds from a hydrocarbon gas mixture at moderate pressures and temperatures in a vacuum chamber. Both are methods for making diamonds in a lab, according to GIA.

Can you tell if a diamond was grown by HPHT?

GIA says markers in a lab-grown diamond allow its scientists to identify which growth method was used. HPHT-grown crystals also typically show cubic faces in addition to octahedral ones. Both are laboratory clues, not something to judge by eye at a store counter.

Where can I get lab-grown diamonds grown by HPHT?

Labrilliante supplies lab-grown diamonds grown by HPHT and CVD to jewelry retailers and brands. IGI- and GIA-certified lab-grown diamonds are available. Send the shapes, sizes and reports you need to info@labrilliante.com or call +1 551-321-8771, and we will tell you what is in stock.