The series "Stones" was created in 2013. Previously, Robert Zandvliet had used works by other artists and positions from art history as reference points for his own work. The depiction of everyday objects, and finally of stones, signified a departure from this idea: the focal point of the paintings is a single, inanimate object that is simple both in its external form and in its structure - its "idea".
Zandvliet's aim is to approach the characteristics of stones, such as heaviness, closed surface or compactness, in a painterly way. For this he uses different techniques and materials.
He crumples the paper of these watercolor works before painting. The resulting finish forms a random and lively structure with the color itself. Combined with the planned prismatic surfaces, this suggests the edges and cracks of stones without directly depicting them. These works place the crystalline shape of stones at their center.
In the paintings created by tempera technique on cotton or linen, Robert Zandvliet applies prismatic structures in deliberately broad, gestural brushstrokes. The paint application is often quite dry, developing a transparent effect. In the paintings, the reproduction of the appearance of stones is background matter. They are rather concerned with questions of their inner constitution and with which painterly means the compactness, weight and other characteristics of stones can be depicted.