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.
Intermediate2-4 weeks
Lapidary Cutting Basics
Complete guide for lapidary cutting basics — step-by-step workflow, tools, checklist, and expert tips to get started.
lapidary artistscab makers
Workflow
Slab on Trim Saw at Target Thickness
1-2 hoursCut slabs 5–8 mm for cabs on trim saw with coolant flow; feed slowly on hard material like agate or jasper.
Grind Cabochon Dome Through Grit Sequence
2-3 hoursDop slab and grind 80 → 220 → 600 grit on wheels; maintain even dome without flat spots on crown.
Polish on Canvas and Inspect Under Light
1 hourPolish with 14k–100k compound on canvas; inspect under incandescent light at angle for remaining scratches.
Tools Used
- Rock Density CalculatorPrimary
Estimate rough stone density to plan slab thickness and feed rate on trim saw for safe cutting.
- Mohs to Vickers Hardness ConverterPrimary
Convert Mohs hardness to select appropriate grit sequence and polishing compound for the stone species.
- Time Duration CalculatorSupporting
Track grinding time per grit stage to develop consistent cabochon production workflow.
- Mineral Hardness IdentifierReference
Confirm stone hardness before selecting dop method and wheel speed to prevent fracture during cabbing.
Checklist
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Preparation
Safety
Technique
Quality
Documentation
Reference Materials
Grit Progression by Stone HardnessTable
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 |
Slab Yield EstimateFormula
Usable slab area ≈ 70% of rough cross-section after removing fracture zones and kerf loss.
Wet Grind OnlyStandard
Silicosis from dry grinding agate and jasper is irreversible — continuous water coolant mandatory on all wheels.
First Cut Matters
Initial slab orientation determines color pattern in finished cab — study rough 10 minutes before cutting.
Never Skip Grits
Jumping 220 to 600 leaves scratches visible only after polish — start over if skipped.
Silica Dust
Dry grinding kills — wet wheels only, N95 if any dry trimming unavoidable.
Safety Notes
- Wear safety goggles when breaking rocks — fragments fly unpredictably.
- Silicosis from agate/jasper dust is permanent — wet grind exclusively and use N95 for trim work.