Fused Silica vs Quartz Glass: How to Choose – custom precision glass machined to drawing with inspection reports. No minimum order; DFM review included with every RFQ.
Engineers rarely need a winner in fused silica vs quartz glass: how to choose – they need the boundary. It runs along purity and UV transmission versus cost: synthetic fused silica wins below 260 nm; fused quartz wins on price for thermal hardware.
Side by side
| Fused Silica | Quartz Glass | |
|---|---|---|
| CTE | 0.55 x 10^-6 /K | 0.59 x 10^-6 /K |
| Service temp | 1,100 C continuous | 1,050 C continuous |
| Transmission | 185 nm – 2.5 um | 260 nm – 2.5 um |
| Hardness | 500 kg/mm2 | 500 kg/mm2 |
| Density | 2.20 g/cm3 | 2.20 g/cm3 |
| Signature trait | near-zero thermal expansion | fused from natural quartz crystal |
The decision axis is purity and UV transmission versus cost. Synthetic fused silica wins below 260 nm; fused quartz wins on price for thermal hardware.
Getting the drawing right
Before sending the RFQ, check these against your drawing:
- Over-specification is the quiet budget killer: a 20/10 scratch-dig face costs roughly three times an 80/50 face, so grade each surface individually.
For the complete framework, see the tolerance design guide and the holes and edges design guide.
Who orders this
The recurring buyers of fused silica vs quartz glass: how to choose: laboratory instruments (cuvettes, sight glasses, stir-cell windows); mems devices (cap wafers, TGV substrates, motion-sensor lids); optical sensors (sensor windows, filter caps, lens covers).
Prefer to sketch it? Our custom glass machining 3D + 2D builder accepts your dimensions directly and routes them to engineering.
Related reading on this site: optical polishing capability, fused silica wafers 2-12 inch, tolerance design guide.
Buyer questions, answered
How fast can prototypes ship?
Machined prototypes ship in 5 – 10 working days. Coated or bonded parts add 1 – 2 weeks depending on queue slots.
What files do you need for a quote?
A dimensioned PDF plus DXF or STEP geometry. If only a sketch exists, our drawing review service formalizes it before quoting.
Do parts ship with inspection data?
Dimensional reports, surface certificates and material certs per melt are available; specify the level on the RFQ.
Which should I choose?
As a rule: synthetic fused silica wins below 260 nm; fused quartz wins on price for thermal hardware. Borderline cases are worth a materials review with our engineers.
Specifications on this page were last reviewed by our engineering team in August 2026.