|Detecting Synthetic Quartz
Synthetic quartz produced by the hydrothermal method has become very common in the market, and we want to be sure that all the amethyst, citrine, ametrine and other types of quartz we sell is completely natural. Our customers trust us to accurately describe the gems we sell, and we take that trust very seriously.
As buyers, we have seen a lot of synthetic quartz offered for sale and we are reasonably good at recognizing the most obvious cases. You will often see synthetic amethyst or citrine in extraordinarily large sizes with perfect clarity, offered at prices too good to be true. Natural amethyst or citrine will typically exhibit color zoning that you won't find in the synthetic material. The synthetic ametrine is often found in colors that you won't see in nature; either the color is extraordinarily vivid, or you will find hues such as blue and green which do not occur naturally.
However, not all synthetic quartz is so obvious. Some of it looks just like natural quartz, which is not surprisingly, since it is real quartz (just not naturally occurring). Distinguishing natural from synthetic quartz is actually a challenge, even for gemology labs, especially with very clean specimens. Many gem labs will simply issue an "undetermined" verdict when analyzing a quartz sample, since they don't have the expertise to reliably identify synthetic material.
Synthetic Green Quartz
The best labs use a combination of traditional analysis and advanced instruments to reach a definitive conclusion about a quartz sample. The traditional analysis looks for distinctive "breadcrumb" inclusions left by the seed crystal used to grow synthetic quartz; color zoning usually found only in natural quartz, and the presence of so-called "Brazil twinning" which is typical of natural quartz crystals. Then infrared spectroscopy is used to graph the wavelengths of infrared light that the quartz absorbs. Synthetic and natural quartz usually exhibit distinctive patterns of absorption.
Though no single test for quartz is definitive, performing a number of tests is nearly always conclusive. The testing is time consuming and somewhat expensive. But we have samples tested for all the different types of quartz we sell. It is the only way we can be sure that we are selling only natural quartz.