Rutile is a titanium-containing oxide, which is occasionally encountered as both a mineral specimen and faceted gemstone. However, the mineral tends to be better known when present as fibrous inclusions within other gemstones and, when these are present in sufficient size so as to be visible with the naked eye, the specimen is referred to as “rutilated” (e.g. rutilated quartz, rutilated topaz, etc.). In addition, microscopic fibrous rutile inclusions are responsible for cat’s eye chrysoberyl’s highly desirable chatoyancy, as well as the asterism effect observed within star rubies and sapphires.

For a brief period during the mid-twentieth century, synthetic rutile was developed as a diamond simulant and sold under the trade name of “titania”. However, the material’s low hardness (6.0 to 6.5) and suspiciously high dispersion (0.33) meant that it was quickly superseded by other artificial imitations such as cubic zirconia (CZ).