Drying our extracted compound on a vacuum after a diazonium coupling reaction.
The first picture shows the solid beginning to show cracks after 15 minutes of drying on vacuum on the Buchner funnel. The second picture is after 45 minutes of drying and the solid now has widespread cracks.
These cracks are called "desiccation cracks" and are normally seen in dried mud. They form due to a solid thoroughly drying out, which causes contraction and thus the solid ‘cracks’.