The Thames & Kosmos Rock Tumbler

• Turn rough rocks into glossy gemstones while exploring erosion, weathering, and the rock cycle

• Quiet, leak-proof, noise-reducing barrel plus built-in timer with presets up to seven days for set-and-forget polishing

• Durable, long-life motor handles repeated runs and a variety of media: rocks, glass, wood, and more

• Start polishing on day one with an included gem mix (tiger’s eye, aventurine, rose quartz, and others) and a four-stage grit system

• USB-C power and 450 g (≈1 lb) capacity make it compact, efficient, and easy to place on a desk or countertop

• Create keepsakes with jewelry settings; perfect as a STEM geology kit for curious kids and beginner rockhounds

• Illustrated manual and poster teach rock types, crystal formation, tumbling stages, contamination avoidance, and finishing tips

• Great upgrade path with compatible refill packs to keep projects rolling

Specifications

• Ages: 8+

• Experiments: 5

• Piece Count: 21

• Capacity: 450 g (over 1 lb)

• Power: USB-C (no batteries required)

• Timer: Up to 7 days (multiple settings)

• Product Dimensions: 9 × 9.6 × 4.3 in.

• Product Weight: 4.4 lb

• Manual Pages: 6

• Manual Dimensions: 5.5 × 11.7 in.

• Country of Origin: China

• Year Released: 2025

What’s in the Box?

• Rock tumbler with leak-proof, noise-reducing barrel and built-in timer

• Assorted natural rocks (e.g., tiger’s eye, aventurine, rose quartz, and more)

• Four polishing grits: coarse, medium, fine, and final polish

• Jewelry settings to turn polished stones into accessories

• Illustrated manual and educational poster

• USB-C power cable

Software and Docs

Download Manual (PDF)