material_sets/sand needs:

• crushed.png
• crushed_centrifuged.png
• crushed_overlay.png
• crushed_purified.png
• dust.png
• dust_impure.png
• dust_impure_overlay.png
• dust_pure.png
• dust_pure_overlay.png
• dust_small.png
• dust_tiny.png

The following are blank and do not need to be overwritten:

• dust_overlay.png
• dust_small_overlay.png
• dust_tiny_overlay.png

Suggestion

Copying the textures from the Dull Material Set seems like the simplest solution.