Lab Grown Buying Guide

Gemstones are a miracle of nature: a miracle that has now been recreated  by man.

Chatham is proud to be the pioneer of lab-grown gemstones.

These gemstones have the same physical, chemical, and optical properties as mined gems do. We don’t “make” gems. We control the environment so that crystals can grow naturally: recreating the conditions in which gems grow in the earth.

The process of growing gem crystals in a laboratory rather than mining them is a bit like making ice in your freezer instead of finding it in a lake. You place the starter material, water, in a container, and put the container into a controlled environment: your freezer. Create the right conditions of temperature and time and ice crystals will form. The freezer ice will usually be cleaner and more perfect than lake ice because you can carefully control the environment. But it’s still ice, just like the ice that forms in nature. In a way, what we do is a sophisticated high-tech version of freezing water to form ice.

One of the benefits of lab-grown gemstones is that they have less of an impact on the environment than mined gems.

Growing Diamond Crystals

Unlike the other gems we grow, diamond is a single element: carbon. In some ways that makes things easier. The fewer variables there are, the easier the growth process. We grow diamond using two processes: HPHT (High Pressure, High Temperature_ and CVD, or Chemical Vapor Deposition.

In the HPHT process, we grow crystals as large as 10 carats using 50 kilobars or 725,000 PSI of pressure at 1300 degrees Celsius. If you tried to grow diamond without high pressure, you’d just get graphite. The equipment required is massive: our largest diamond press is three stories tall! It produces about 100 carats at a time in about a week to ten days. Diamonds that grow this way can be remarkably pure.

To grow colorless diamond crystals using the CVD process, methane gas is subjected to high-energy plasma radiation. Methane is CH4: it has one carbon atom and four hydrogen atoms. We use microwave energy heat to break the atomic bonds in the methane and free the carbon to float down and attach to a diamond seed, growing a diamond crystal atom by atom.

When everything goes well, it takes about 10-12 days to produce 140 carats of crystals that are 8-9 carats each. But there are still huge technical challenges that everyone who uses this growth method faces. That’s why production of diamonds using CVD is still quite limited. And like mined diamond, there is a lot of variety in color and clarity, which allows us the ability to offer an array of qualities.

Growing diamonds is challenging and expensive. The price difference between Chatham and mined diamonds of similar quality can be dramatic, especially in finer qualities. The difference generally varies from about 30% – 80% depending on the size, shape and quality of the diamond. The price difference increases substantially as the weight and quality of the diamond rises.

Environmental Impacts

Chatham has been operating alongside mined gemstones for 80 years. We have always stood behind the notion that our products are merely an alternative and not a substitute. It is up to the consumer to make their choice after weighing their options.

We have received a great number of inquiries regarding the ecological impacts made by growing diamonds, as interests rise. The truth is, very few things in the jewelry industry are inherently eco-friendly. Some just leave lighter carbon footprints than others while also doing less harm to the planet as a whole.

As stated, lab grown diamonds are grown two ways: under enormous pressures, 750,000 psi at 1300 C, or from the breakdown of Methane gas using microwave technology. In recent years, Stanford University put out a report that investigated these processes (independently from any grower) and concluded that even with all the equipment factored in (the equipment is not destroyed but reused and has a very long life) the carbon footprint of a lab grown diamond is only 20% of what is expanded in natural diamond mining. If one were to remove the initial equipment construction, that footprint would easily be in the single digit percentages. The pressures are created hydraulically and easily achieved since a liquid cannot be compressed. In the case of CVD, high temperatures are reached using microwaves to excite and breakup Methane and is very similar to that used in an everyday kitchen, but on a larger scale. The difficulty in producing lab grown diamond is not in energy expanded but in brainpower. The chemistry and physics are very complex while the computerization of the process is extremely delicate. Maintaining temperatures and pressures manually is impossible to do accurately and computers are relied on for this purpose. But nobody writes code ware on “how to grow a diamond“; very talented people must create it. The code ware is not shared with anyone and is a closely guarded part of the process.

Alternatively, an enormous amount of energy is consumed to extract diamond-bearing rocks from volcanic pipes. Approximately 10 tons of rock must be extracted and crushed for each carat of diamond rough found. These extractions are so immense they are visible from outer space, open pits spanning miles, all left like scars on the earth.

Peace of Mind

Chatham diamonds are grown in our Research Laboratories all over the world: San Francisco, Russia, Japan, and Siberia. Our diamond rough is then sent to either China or Russia for faceting by highly trained cutters using specialized equipment. Some of these cutters have been with us for over 30 years.

Chatham lab grown diamonds are excluded from our valued Lifetime Warranty Guarantee. While diamond is the hardest material in the gemstone world, it is not indestructible. Diamonds are brittle and will cleave or chip easily if abused. It is also at minimum 10 times more expensive to produce a diamond than it is to mine it. Consequently, we felt it was prudent to withhold the unlimited warranty on our diamonds because of this inherent problem. We have also learned it is impractical to measure the skill level of stone setters and manufacturers, thus we followed the trade with no warranties on diamond except for our finished jewelry construction quality, which is up to one year.

Every gemstone made by Chatham has the identical crystalline structure and composition of its natural counterpart. Same hardness, same toughness, and same chemical makeup. Treat them as you would a gemstone mined from the earth, with tender, loving care.