Evaluate Rough for Fractures and Yield
30 minutesInspect rough under bright light for internal fractures, inclusions, and color zoning; mark slab cut lines with aluminum pencil.
Field context
This workflow is part of 3 niche fields
Complete guide for lapidary cutting basics — step-by-step workflow, tools, checklist, and expert tips to get started.
Inspect rough under bright light for internal fractures, inclusions, and color zoning; mark slab cut lines with aluminum pencil.
Cut slabs 5–8 mm for cabs on trim saw with coolant flow; feed slowly on hard material like agate or jasper.
Dop slab and grind 80 → 220 → 600 grit on wheels; maintain even dome without flat spots on crown.
Polish with 14k–100k compound on canvas; inspect under incandescent light at angle for remaining scratches.
Estimate rough stone density to plan slab thickness and feed rate on trim saw for safe cutting.
Convert Mohs hardness to select appropriate grit sequence and polishing compound for the stone species.
Track grinding time per grit stage to develop consistent cabochon production workflow.
Confirm stone hardness before selecting dop method and wheel speed to prevent fracture during cabbing.
Standard lapidary grit sequence for common cab materials.
| Grit | Purpose | Typical Time |
|---|---|---|
| 80 | Rough dome shape | 10–15 min |
| 220 | Refine curvature | 10 min |
| 600 | Pre-polish | 8 min |
| 14k compound | Final polish | 5 min |
Initial slab orientation determines color pattern in finished cab — study rough 10 minutes before cutting.
Jumping 220 to 600 leaves scratches visible only after polish — start over if skipped.
Dry grinding kills — wet wheels only, N95 if any dry trimming unavoidable.