Silk Brush
Silk Brush is an uncommon tool.
Can be used once to excavate a fossil, with moderate success.
Sources
Can be obtained via 
Spawnable Item Pack or 
Technical Information
- In-game ID:
ct_alta_silk_brush - Power:
2.5 - Rarity:
Uncommon - Tags:
alta,fossilbrush,uncommon - File:
/items/active/alta/tools/brushes/silk_brush/ct_alta_silk_brush.activeitem