Synthetic Rutile

1. Chemical Composition Titanium Dioxide - TiO2
2. Classification / Type The material is found abundant as inclusions (silk, needles, crystals, etc.) in number of gemstones preferably in quartz, tourmaline, ruby and sapphire but large facet table crystals are quite rare therefore gemological importance lies in the synthetic counterpart produced by flame fusion method.
3. Colors / Varieties All colors, generally colorless with a yellow tinge.
4. Crystal System Tetragonal System
5. Hardness 6 - 6.5
6. Specific Gravity 4.20
7. Cleavage / Fracture Distinct
8. Optic Character Anisotropic, D.R.; Uniaxial Positive
9. Lustre Vitreous
10. Refractive Index / Birefringence 2.616 - 2.903 / 0.287
11. Pleochroism Weak
12. Dispersion 0.290 (high fire)
13. Magnification Generally clean, strong doubling giving a hazy appearance, dispersive fire.
14. U.V. Fluorescence Inert.
15. Cause of Color As per dopant used.
16. Spectrum Not diagnostic.
17. Treatment (Enhancement) Dark colored boules of synthetic rutile are heated to give the light yellow color. Natural rutile is generally brown in color which is heated to give yellow color.
18. Specific Tests & Remarks Very high doubling and dispersive fire.
19. Synthesis Flame Fusion Method.
20. Simulants (with key separation tests) G.G.G. (dispersion, doubling, S.G.), Y.A.G. (dispersion, doubling), Synthetic Cubic Zirconia (S.G., dispersion, doubling), Diamond (dispersion, doubling), Strontium Titanate (dispersion, doubling), Sphene (doubling, dispersion, inclusions), Zircon (dispersion, spectrum), etc.
21. Geological Occurrence Natural rutile as inclusions in quartz, tourmaline and corundum. Synthetic rutile in a laboratory.
22. Sources -
23. Cuts & Uses Facetted cuts, etc.