FDA
FDA 21 CFR 1040.10 - Laser Product Performance Standards
Todd DunningMAUnited States
Optical Materials for Laser SystemsPublished
Dec 16, 2025
Gneiss Laser Cleaning
Gneiss stands out with its durable structure and low porosity, allowing laser cleaning to strip away contaminants efficiently while safeguarding the stone's natural integrity.
Laser-Material Interaction
Thermal Destruction
1,273
K
273
1,273
2,300
Laser Absorption
0.3
0.06
0.3
1.3e6
Laser Damage Threshold
1.8
J/cm²
0.42
1.8
13.1
Ablation Threshold
2.3
J/cm²
0.65
2.3
6.3
Thermal Diffusivity
1.3e-6
m²/s
0
1.3e-6
2e-6
Thermal Expansion
9.2e-6
K^{-1}
6e-6
9.2e-6
12
Specific Heat
840
J/(kg·K)
400
840
1,200
Thermal Conductivity
2.3
W/m·K
0.2
2.3
8
Laser Reflectivity
0.12
0.03
0.12
0.44
Gneiss Laser Cleaning Material Characteristics
Density
2.7
g/cm³
2.2
2.7
3,045
Porosity
3
%
0
3
19.4
Surface Roughness
8
μm
0
8
16
Tensile Strength
120
MPa
1.4
120
15.7
Youngs Modulus
50
GPa
9.8
50
7.9e10
Hardness
1.8
GPa
0.7
1.8
7.3
Flexural Strength
180
MPa
2.2
180
36.6
Oxidation Resistance
8
μm/year
9.5e-5
8
1,547
Corrosion Resistance
0.85
mm/year
6.6e-5
0.85
21
Compressive Strength
120
MPa
2.1
120
220
Fracture Toughness
6
MPa m^{1/2}
0.13
6
2
Electrical Resistivity
1e12
Ω·m
9.5
1e12
1e15
Gneiss surface magnification
Before Treatment
At 1000x magnification, the gneiss surface appears coated with a thick layer of dark contaminants that obscure underlying textures. Fine particles cling tightly to the rough contours, creating uneven patches and dull spots across the view. This contamination hides the natural banding patterns that define gneiss.
After Treatment
After laser treatment, the same surface reveals a clear, restored texture with distinct mineral bands now fully exposed. Smooth areas emerge where contaminants once dominated, allowing the rock's layered structure to stand out sharply
Regulatory Standards & Compliance
ANSI
ANSI Z136.1 - Safe Use of Lasers
