Alpha-Quartz NAT (Natural quartz crystal)
Grade
Pick when a natural-origin or very large single-domain blank is required; yield is low because of inclusions, twinning and veils.
Values for the NAT condition
Other Alpha-Quartz tempers and conditions
Alpha-Quartz is listed in 5 conditions; see the grade overview at Alpha-Quartz.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
NATThis page Natural quartz crystal | Pick when a natural-origin or very large single-domain blank is required; yield is low because of inclusions, twinning and veils. | — | 48 | 0 | 1,120 HV | 8 W/m·K |
X-CUT / Y-CUT | Standard cut for waveplates and Wollaston/Rochon polarizers, where the optic axis lies in the plate plane. | — | 50 | 0 | 1,120 HV | 6 W/m·K |
SYN-OPTDefault Cultured (hydrothermal) optical-grade single crystal | Default choice for waveplates, polarizing prisms and UV–NIR windows: inclusion-free, striae-free cultured crystal with reproducible birefringence. | — | 55 | 0 | 1,150 HV | 8 W/m·K |
electronic-grade swept cultured quartz (premium Q, low Al/alkali) | Use for precision oscillators, filters and radiation-hard resonators where infrared Q and low alkali-ion content control aging. | — | 55 | 0 | 1,150 HV | 8 W/m·K |
Plate normal parallel to optic (c) axis | Choose when light must travel along the optic axis (no birefringence) or for optical-rotation and etch-pit work. | — | 60 | 0 | 1,180 HV | 11 W/m·K |
What is Alpha-Quartz NAT?
Alpha-Quartz NAT is Alpha-Quartz in the NAT grade — pick when a natural-origin or very large single-domain blank is required; yield is low because of inclusions, twinning and veils. Alpha-Quartz NAT has a tensile strength of 48 MPa (6.96 ksi), stronger than 51% of glass grades. Elongation at break is 0% and the elastic modulus is 86 GPa (12.5 Msi). Alpha-Quartz NAT has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 52% of glass grades. It melts at 1,710°C (3,110 °F). SYN-OPT is the default condition FabDigit quotes; NAT is available on request or by drawing note.
Advantages
- Conducts heat well — 8 W/m·K (4.62 BTU/hr·ft·°F), better than 76% of glass grades
Limitations
- Difficult to machine — 5/100, worse than 92% of glass grades
- High embodied carbon — 18 kg CO₂/kg, worse than 76% of glass grades
Alpha-Quartz NAT properties
Typical room-temperature values for Alpha-Quartz NAT; 15 are specific to this condition. Other listed values are Alpha-Quartz reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
Alpha-Quartz NAT has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 52% of glass grades. It melts at 1,710°C (3,110 °F).
Mechanical13
Alpha-Quartz NAT has a tensile strength of 48 MPa (6.96 ksi), stronger than 51% of glass grades. Elongation at break is 0% and the elastic modulus is 86 GPa (12.5 Msi).
Thermal5
Alpha-Quartz NAT is rated for continuous service to 500°C (932 °F). It conducts heat at 8 W/m·K (4.62 BTU/hr·ft·°F), better than 76% of glass grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical5
Alpha-Quartz NAT is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (90/100), better than 73% of glass grades.
Sustainability4
Producing a kilogram of Alpha-Quartz NAT takes about 250 MJ of energy and emits 18 kg of CO₂ — more than 76% of glass grades. Typical recycled content is 0%.
Manufacturability2
Alpha-Quartz NAT's machinability is not recommended (5/100, worse than 92% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alpha-Quartz NAT
Is Alpha-Quartz easy to machine?
Diamond only — ID/wire sawing, core drilling and lapping with loose SiC/diamond abrasive; brittle with rhombohedral cleavage, so keep light loads and flood coolant, and orient cuts to the crystallographic axes within arc-minutes.
Can Alpha-Quartz be welded?
Not weldable or fusible without destroying the crystal; join by optical contacting, UV-cure or epoxy cementing, or by metallized/solder mounting for resonators.
Can Alpha-Quartz be formed, bent or molded?
No hot forming — the material is grown hydrothermally to near-net boules and heating past 573 °C causes the α→β inversion and twinning; all shaping is subtractive.
What surface finishes work on Alpha-Quartz?
Pitch or CeO2 polishing gives λ/10 flats and <1 nm Ra; ammonium-bifluoride or HF etch removes subsurface damage and reveals twins; AR or metal electrode coatings are applied by sputtering/evaporation.
Alpha-Quartz chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Alsubstitutional Al–alkali centres control Q and radiation sensitivity | ≤ 0 | 5×10⁻⁴ |
| Naremoved by electrodiffusion (sweeping) | ≤ 0 | 2×10⁻⁴ |
| Li | ≤ 0 | 2×10⁻⁴ |
| Fecolouring impurity | ≤ 5×10⁻⁴ | 1×10⁻⁴ |
| OHstructural water; measured as IR alpha-3500 Q value | ≤ 0.01 | 0 |
| SiO2crystalline alpha polymorph; Si 46.7 wt%, O 53.3 wt% | ≥ 99.99 (balance) | — |
Alpha-Quartz NAT — frequently asked
What is Alpha-Quartz NAT used for?
Alpha-Quartz NAT is typically used for waveplates/retarders, polarizing prisms, piezoelectric resonators and UV optics. In short: birefringent piezoelectric SiO2; axis-oriented optical cuts; 573 °C inversion limit.
What is the tensile strength of Alpha-Quartz NAT?
Alpha-Quartz NAT has a typical tensile strength of 48 MPa (6.96 ksi) — stronger than 51% of glass grades. Strength varies by condition: see the 5 listed tempers.
Is Alpha-Quartz NAT easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 92% of glass grades). Diamond only — ID/wire sawing, core drilling and lapping with loose SiC/diamond abrasive; brittle with rhombohedral cleavage, so keep light loads and flood coolant, and orient cuts to the crystallographic axes within arc-minutes.
Can Alpha-Quartz NAT be welded?
Not weldable or fusible without destroying the crystal; join by optical contacting, UV-cure or epoxy cementing, or by metallized/solder mounting for resonators.
What surface finishes work on Alpha-Quartz NAT?
Pitch or CeO2 polishing gives λ/10 flats and <1 nm Ra; ammonium-bifluoride or HF etch removes subsurface damage and reveals twins; AR or metal electrode coatings are applied by sputtering/evaporation.
Can Alpha-Quartz NAT be formed, bent or molded?
No hot forming — the material is grown hydrothermally to near-net boules and heating past 573 °C causes the α→β inversion and twinning; all shaping is subtractive.
What is the maximum service temperature of Alpha-Quartz NAT?
Alpha-Quartz NAT is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- IEC 60758 — Synthetic quartz crystal: specifications and guide to use — IEC (2016)
- Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- Handbook of Optical Constants of Solids — Academic Press (1998)
- Crystal Quartz (SiO2) optical material datasheet — Crystran / Hilger Crystals (2023)
- Landolt-Börnstein: Elastic, piezoelectric and dielectric constants of quartz — Springer (1979)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.