Low-Type Zircon
Last updated: April 2026
A type of zircon whose crystal structure has been damaged by radioactive elements.
Low-Type Zircon has a specific gravity of 4.00 and a refractive index of 1.780–1.815, with a Mohs hardness of 6.0–7.5. It is singly refractive.
Physical & Optical Properties
RI Range1.780–1.815
SG Range3.90–4.10
SG Typical4.00
Hardness (Mohs)6–7.5
Crystal SystemTetragonal
Optic CharacterSR (Singly Refractive)
Dispersion0.038
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsGreen, Brown, Yellow Orange
SpeciesZircon
Related: Zircon Varieties
Key Differentiators
- Metamict state (damaged crystal lattice)
- Lower RI and SG than high zircon
- Often has a 'sleepy' appearance
Treatments
- Heat Treatment (restores crystal structure — blue/colorless)
Price Context
Natural — low ($/ct)$10
Natural — high ($/ct)$100
NotePer carat; metamict low-type zircon; greenish, lower RI and SG; less desirable than high-type
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
Measurement Guides
Identifying a low-type zircon? GemID walks through these tests in order — RI, SG, fluorescence, and more.
Try GemID Free →Studying for the GIA, FGA, or FEEG practical? Low-Type Zircon is one of the 130 species in GemID’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →