Leonardo da Vinci may have used toxic pigments when he created his most famous painting, The Mona Lisa. The results of the study were published in the scientific journal Journal of the American Chemical Society, writes Ars Technica.

Da Vinci is well known for using unusual methods and substances to create his masterpieces. So it’s no surprise that scientists have made similar discoveries while studying his paintings.

“The Mona Lisa is in extremely good condition for its age. Both restorers and da Vinci researchers are eager to learn as much as possible about the materials the master used to create it.

To do this, the scientists examined a micro sample of the painting using X-ray diffraction and infrared spectroscopy.

In it, they found a rare compound called plumbonacrit. It is formed when lead oxide and oil interact. This is the first time plumbonacrite has been found in an Italian Renaissance painting. According to scientists, this suggests that Da Vinci may have been the pioneer of this technique.

As you know, the artist painted the legendary Mona Lisa around 1503. The painting is considered one of the most famous and priceless works of art in the world. It is exhibited in the Louvre and protected by special bulletproof glass.