What is coloured glass and how do its colours work together? This project is about metal oxides, how they constitute glass colours, and how they can be arranged in a system. In addition to the parameters of colour such as hue, brightness and purity, glass has the added dimension of the material: metal oxides, the chemical elements responsible for the colours, have an effect on the network structure of the glass and its behaviour such as viscosity and malleability. Depending on which metal oxides are mixed, rather bluish, yellowish, greenish, or reddish hues are created, which in turn can be darker or lighter, saturated or desaturated. Additionally, the working properties of the glass will change. The resulting colour system, that not only shows the colours but also illustrates this behaviour, makes it easier for everyone who works with glass to classify the colour shades and is also a tool for explaining to children or non-professionals how chemistry, glass and colour are connected.