Published on the Italian Gemological Review, issue N°8, Jan 2020
Far from abandoning the top of the ranking of the most popular topics, the problem of identifying synthetic diamonds, especially in small sizes, remains constantly topical. Until a few years ago, producing colorless synthetic diamonds free of single nitrogen impurity was very complicated. Now the situation is changed. The HPHT method, the cheapest, was not effective
on a large scale and the CVD was still uneconomical to grow the smaller material.