Saving Colours and Textures used in a Model

[ChrisDizon]

This may help

Creating SKM file with mac

Set the Materials window to show In Model. Then below click on the List dropdown and choose Duplicate. That will generate a folder with the currently In Model materials as .skm files. Alternatively you can select a single In Model material so it shows in the larger square to the left of the palette at the bottom of the Colors panel, change to the desired collection and drag the material up into the collection.

Also…

Adding Materials to SketchUp - Skill Builder

Creating Custom MATERIAL LIBRARIES in SketchUp with Material Collections!

Cheers