Material Guide

Fused Silica vs Fused Quartz: What’s the Difference?

Fused silica and fused quartz are often used interchangeably, but they differ in how they are made and in UV performance. Learn the JGS1 / JGS2 / JGS3 grades and how to choose.

1. Terminology: Synthetic vs Natural

The names describe the origin of the raw material, and both end up as amorphous SiO₂ glass:

Fused silica — made from synthetic silicon compounds (e.g. SiCl₄ flame hydrolysis). Extremely pure, low metallic impurities, best deep-UV transmission. Often sold as Suprasil, Spectrosil or JGS1.
Fused quartz — made by melting natural quartz crystal. Slightly higher metallic trace levels; fine for most UV-Vis but with a higher UV cut-off (some grades only transmit from ~200–220 nm).
The overlap — many suppliers (including scuvette) use "fused quartz" loosely for both. Always check the grade, not the label.

2. The Grades: JGS1 / JGS2 / JGS3

Grade	Origin	UV cut-off	Best for
JGS1 (equivalent to Suprasil/Spectrosil)	Synthetic fused silica	~190 nm	Deep-UV & fluorescence work, highest purity
JGS2 (equivalent to Vitreosil/Heralux)	Natural quartz, flame-fused	~200–220 nm	Routine UV-Vis above 220 nm
JGS3 (IR-grade)	Natural quartz, vacuum-fused	~220 nm (UV) / transmits to 3500 nm	IR spectroscopy, near-IR work

scuvette standard cells use Japanese-imported JGS1 synthetic fused silica — the same grade class as Suprasil and Spectrosil — so one cell covers 190–2500 nm for both UV-Vis and fluorescence.

3. UV Cut-off & Transmission in Practice

For most lab work the practical difference is what happens below 220 nm:

Measurements at 200–220 nm (some pharmaceuticals, peptide bonds) — JGS2 may start to absorb; JGS1 is safe.
Measurements below 200 nm (e.g. 190 nm, some gas-phase work) — only synthetic fused silica (JGS1 class) transmits.
Measurements above 250 nm — any grade works; choose on price.

4. Which to Choose

Your measurement	Recommended grade	scuvette option
Deep UV (< 220 nm)	JGS1 synthetic	10 mm standard JGS1 cells from $35
Routine UV-Vis (220–800 nm)	JGS1 or JGS2	JGS1 standard — one cell for everything
IR / near-IR (up to 3500 nm)	JGS3 IR-grade	IR cuvette series
Fluorescence	JGS1 (low autofluorescence)	Fluorescence cells from $90

5. FAQ

Is scuvette quartz "real" fused silica?

Yes. Our standard line uses Japanese-imported JGS1 synthetic fused silica, and we publish the material grade on every product page.

Why does grade matter if I only measure at 400 nm?

It mostly does not — visible-only work can use lower grades or even glass. Grade matters for UV and fluorescence.

Can you supply JGS2 or JGS3 cells?

Yes — JGS3 IR cells are a standard line, and JGS2 can be made to order. Contact us with your wavelength range.

Not sure which quartz grade your application needs?
Send us your instrument model and sample type — our engineers will reply within 1 business day with the right specification and a firm price. Contact Scuvette →

Need a hand? Our engineers can help you select the right cuvette for your instrument and application — or supply custom optical cells to your drawing. Contact Scuvette →