Quartz (natural quartz).
- Possesses a low Boron density as below 0,1 ppm, which guarantees a clean background in Boron-11 NMR studies
- 2× less dielectric constant than borosilicate glass, which helps improve the quality
- Not recommended for EPR studies
- Caps are not recommended for use with samples dissolved in chloroform-d or acetone-d6
Extremely low thermal expansion rate and high tensile strength. This feature makes quartz tubes 14 times more robust during cooling/heating process than corresponding Precision glass tubes. Naturally occurring quartz maintains over 85% transmission rate (10 mm thickness, with consideration of reflection loss) above 265 nm¹·², which makes quartz tubes preferable in photochemistry studies.