Wie hängen sie zusammen

In the upper right-hand compartment of Beuys' tool cabinet lies a bag of artificial ultramarine, a blue-coloured powder for painters. That's strange because Beuys' art is not exactly famous for its bright colours. What significance might the powder have had for him? Was he interested in the chemical process used to produce artificial ultramarine? Was the symbolism important to him or perhaps the long history of ultramarine, which artists have been using for over 1000 years?