Alpha-Quartz vs N-BK7
Glass · grade comparison
Alpha-Quartz and N-BK7 are both glass grades. Alpha-Quartz is the stronger of the two: tensile strength 55 MPa (7.98 ksi) against 50 MPa (7.25 ksi) for N-BK7, about 10% more. Alpha-Quartz is harder — 1,150 HV against 610 HV for N-BK7 — which matters for wear surfaces and threads. N-BK7 is lighter (2.51 g/cm³ vs 2.65 g/cm³ for Alpha-Quartz) and Alpha-Quartz is stiffer (87 GPa vs 82 GPa). On the shop floor, N-BK7 machines more easily (poor vs not recommended) and N-BK7 sits in a lower cost tier (standard, $$) than Alpha-Quartz (high, $$$$).
Alpha-QuartzChoose it when strength drives the design, or when surface hardness matters.
N-BK7Choose it when weight is the constraint, or when the part is machined in volume.
Alpha-Quartz vs N-BK7: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Compressive Strength
Flexural Strength
Shear Strength
Hardness, Vickers
Hardness, Knoop
Hardness, Mohs
Same in both: Elongation at Break 0% · Fracture Toughness (K_IC) 0.85 MPa·√m0.77 ksi·√in
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Refractive Index
Same in both: Light Transmission 92% · Porosity 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Min Service Temperature
Same in both: Max Service Temperature (continuous) 500°C932 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Volume Resistivity 1×10¹⁴ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Same in both: Polishability 95 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every glass grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Alpha-Quartz | N-BK7 |
|---|---|---|
| Default condition | — | Annealed Glass |
| Relative cost | $$$$ High | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Alpha-Quartz vs N-BK7 — frequently asked
Is Alpha-Quartz stronger than N-BK7?
Yes. Alpha-Quartz has a typical tensile strength of 55 MPa (7.98 ksi) against 50 MPa (7.25 ksi) for N-BK7 — about 10% more.
Which is cheaper, Alpha-Quartz or N-BK7?
N-BK7 is the lower-cost material: it sits in the standard tier ($$) while Alpha-Quartz is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, Alpha-Quartz or N-BK7?
N-BK7. Its machinability rates poor (18/100) against not recommended (6/100) for Alpha-Quartz.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Alpha-Quartz and N-BK7 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.