He would often spend a whole day settling and resettling in their cases the various stones that he had collected, such as the olive-green chrysoberyl that turns red by lamplight, the cymophane with its wirelike line of silver, the pistachio-coloured peridot, rose-pink and wine-yellow topazes, carbuncles of fiery scarlet with tremulous, four-rayed stars, flame-red cinnamon-stones, orange and violet spinels, and amethysts with their alternate layers of ruby and sapphire.

He loved the red gold of the sunstone, and the moonstone's pearly whiteness, and the broken rainbow of the milky opal.

He procured from Amsterdam three emeralds of extraordinary size and richness of colour, and had a turquoise de la vieille roche that was the envy of all the connoisseurs.
He discovered wonderful stories, also, about jewels.

In Alphonso's Clericalis Disciplina a serpent was mentioned with eyes of real jacinth, and in the romantic history of Alexander, the Conqueror of Emathia was said to have found in the vale of Jordan snakes "with collars of real emeralds growing on their backs." There was a gem in the brain of the dragon, Philostratus told us, and "by the exhibition of golden letters and a scarlet robe" the monster could be thrown into a magical sleep and slain.

According to the great alchemist, Pierre de Boniface, the diamond rendered a man invisible, and the agate of India made him eloquent.