When it comes to laser engraving on stone—from rugged granite to delicate marble—choosing between fiber and CO2 lasers can make or break your project's precision, depth, and finish. Both technologies excel in different scenarios, but understanding their wavelengths, power delivery, and material interactions is key to selecting the right one. In this breakdown, we'll compare the two head-to-head, highlight their strengths for various stone types, and recommend when to pick each for optimal results in 2025.

Quick Specs Comparison

Data sourced from industry benchmarks (e.g., Epilog, Trotec, and user tests on forums like Laser Pointer Forums, 2024-2025 reviews).

How Fiber Lasers Work on Stone

Fiber lasers use a solid-state diode-pumped source to emit a tightly focused infrared beam, ideal for high-energy absorption in reflective or dense materials. On stone, they vaporize surface material quickly, creating deep, clean marks without much residue.

• Pros for Stone:
• Superior Depth and Contrast: On dark, polished stones like black granite or basalt, fiber lasers produce crisp, frosted engravings with high contrast—perfect for memorials or signage. Depths can reach 0.5mm in a single pass, outpacing CO2.
• Speed and Efficiency: Engrave large areas (e.g., a 12x12" headstone) in minutes, thanks to high pulse frequencies.
• Portability: Compact models like the ComMarker B4 fit on a workbench, making them great for field work on monuments.
• Cons for Stone:
• Limited Absorption: Light-colored stones (e.g., white marble, limestone) reflect the IR beam, resulting in shallow or uneven marks. Pre-treatment like painting or annealing is often needed.
• Rougher Finish: Can leave micro-cracks or a "sandblasted" texture on softer stones like slate, less ideal for photorealistic images.
• Not Universal: Struggles with veined or translucent stones, where CO2 shines.

Real-world example: A 30W fiber laser etched a granite plaque with 0.4mm depth at 500mm/s, per a 2025 Monport user review—ideal for durable outdoor use but required multiple passes on marble.

How CO2 Lasers Work on Stone

CO2 lasers generate their beam via gas excitation, producing a longer wavelength that's readily absorbed by organic and inorganic non-metals. This makes them a staple for stone engraving, as the beam heats and vaporizes the surface, forming a frosted, etched layer.

• Pros for Stone:
• Versatility Across Types: Handles everything from hard granite (Mohs 6-7) to soft marble (Mohs 3-5) and textured slate with ease. Produces smooth, high-contrast results on polished surfaces without pre-treatment.
• Photorealistic Quality: Excellent for grayscale images and intricate designs; the even ablation creates subtle shading, outperforming fiber on varied stones.
• Scalability: Higher wattage models (60W+) tackle thick slabs or deep etches via multi-passes, with minimal heat damage.
• Cons for Stone:
• Shallower Depth: Maxes out at 0.3mm per pass, so ultra-deep engravings (e.g., for heavy weathering) require time-intensive layering.
• Slower Operation: Best speeds are slower than fiber, extending job times for large projects.
• Bulkier Setup: Larger footprint and exhaust needs make them less portable for on-site stone work.

Case study: The xTool P2 (55W CO2) engraved a marble award with fine 0.2mm details at 300mm/s, yielding photo-like clarity—praised in 2025 Reddit threads for hobbyist marble projects.

Head-to-Head: When to Choose Each

• Pick Fiber If: You're focusing on dark, uniform stones like granite or basalt for deep, fast engravings (e.g., cemetery markers, industrial plaques). It's the go-to for professionals prioritizing speed and depth on metals-adjacent projects. Budget tip: Start with a 20-30W model like the xTool F1 for hybrid use.
• Pick CO2 If: You need all-around stone versatility for mixed projects involving marble, slate, or light stones (e.g., custom tiles, awards). Ideal for creators valuing detail and ease over raw power. Entry point: A 50W OMTech unit covers 90% of hobby needs.

Hybrid note: Some advanced setups combine both (e.g., LaserPecker's dual-laser), but for pure stone, sticking to one based on your primary material saves hassle.

Final Verdict: CO2 Edges Out for Most Stone Work

While fiber lasers dominate in depth and speed for dark granites, CO2 lasers are the best overall choice for stone engraving due to their unmatched versatility and superior finish across granite, marble, slate, and beyond. They handle the "from granite to marble" spectrum without compromises, making them essential for artists, sign makers, and memorial specialists.

If your workflow skews toward high-volume dark stone jobs, invest in fiber. Otherwise, a solid CO2 setup will future-proof your engravings. Test samples first—stone variability is the real wildcard. Ready to etch? Dive into models like the OMTech Polar (CO2) or ComMarker B4 (fiber) and transform stone into legacy today!