Becoming Citrine: The History of Heat Treating in Brazil
Written by Melissa Robak
May 14, 2021
Adapted from verbal storytelling passed down from through generations and retold by multiple miners, farmers, and processors
The history of Citrine is so much bigger than the world we think of today. To understand and appreciate this beautiful stone, we must take a step back in time, to before the mineral industry existed in many parts of the world.
Generations ago, Agate was the most valuable mineral in Brazil. Extremely hard, more durable than nearly anything they had access to, it was extremely useful. In addition, the banding and unique look of it made it desirable for rich families around the world. Germany had exhausted their local supply, and trading vessels had discovered the Brazilian deposit in poor farmers fields. They contracted the farmers to hand pick these sought-after treasures from their fields, shipping them back to the factories in Germany on their merchant ships.
Recognizing the opportunity, area farmers spent more and more time in the fields, and so began building outdoor ovens to cook and socialize around in the evenings. An outdoor oven is truly an art form in Brazil, and as these pieces were built, locals would add beautiful local stones to the inside and outside walls of the oven to further heighten the esthetic appeal. Their favorite choice was a lilac purple stone found abundantly in the region called Amethyst.
As the months went by, some farmers noticed that the occasional Amethyst would ‘capture the sun’ by turning bright yellow! Eventually, it was discovered that the heat from the oven would change the color of select pieces of Amethyst. This yellow stone was Citrine.
Citrine was regarded by the farmers as a sign of good fortune and was highly treasured. Not all the Amethyst would change color, it was up to the stone itself, and was thought to bring blessings upon those for whom it transformed.
Today, 95% of the world market of Citrine is heat treated using methods based on that original discover generations ago. Citrine processors spend years on the factory floor learning every element of processing before they are afforded the chance to work with Citrine. 3-5mm crystal chips are removed from a potential stone and tested for color change and grade, taking two to five days, before a cluster or cathedral is selected for heat treatment. Not willing to risk the Amethyst they have already put so many hours into, plus considering the hours involved, they must be sure of their choice.
To impart the warmth of the sun into a piece of Citrine is a job these men and women do not take lightly. It is a time honored tradition that will continue for generations to come.