Purple Fluorite
Purple fluorite is the purple to violet color variety of fluorite, the natural calcium fluoride mineral CaF₂, and one of its most typical colors. Studies attribute the color to colloidal calcium and related color centers produced by natural radiation from trace elements such as thorium and uranium. It looks like amethyst and was once sold as "false amethyst", but it is a different, much softer mineral.
Products made with this material
No products for this material yet.
Full material guide
What the material is, where it comes from or how it is made, identification and care, from the cited sources.
Properties
| Nature | Natural mineral (color variety of fluorite) |
| Mineral species | Fluorite (halide); a color variety, not a separate species |
| Chemical formula | CaF₂ |
| Color | Light lilac to deep purple and violet; often banded with other colors |
| Cause of color | Colloidal calcium and 2F⁻ color centers formed by irradiation (linked to thorium and uranium) |
| Mohs hardness | 4 |
| Specific gravity | About 3.18 (3.0 to 3.25 for impure massive material) |
| Refractive index | 1.432 to 1.434 (isotropic) |
| Cleavage | Perfect in four directions (octahedral) |
| Possible treatments | Heating (about 100–150 °C) can lighten dark color; irradiation can darken colorless or pale material to blue, green or purple; decorative objects may be coated, dyed or impregnated with plastic |
Origins & sources
Purple fluorite occurs at fluorite localities worldwide. The International Gem Society cites banded violet material in calcite from Ontario (Canada), violet fluorite from Rosiclare, Illinois (USA), purple from Missouri and a 118 ct purple gem from England at the Smithsonian; blue-purple color-change fluorite from Benxi, Liaoning, China has been studied.
Identification
Purple fluorite has been offered as amethyst. It is separated by its very low refractive index (about 1.43), single refraction, low hardness (4) and perfect cleavage; scratch tests should never be done on finished gems. Some blue-purple fluorite shows a color change to reddish purple under incandescent light. Fluorescence is common but not diagnostic, since not all fluorite fluoresces. Color can be lightened by heating or deepened by irradiation, and decorative pieces may be coated, dyed or plastic-impregnated.
Care
Like all fluorite, it is soft (Mohs 4) and cleaves easily, so ring wear is not recommended; pendants, earrings and protective settings suit occasional wear. Store it apart from harder gems and out of strong light, since some fluorite fades with prolonged light exposure. Fluorite is slightly soluble in water: do not soak it, clean it only with a warm damp cloth, mild detergent and a soft brush, and avoid mechanical cleaning systems.
History
Mindat records "false amethyst" as an old name for cut purple fluorite (Chester, 1896).
Cultural meanings
Pascle, a Japanese retailer, says fluorite is sometimes called the "stone of genius", and that purple fluorite is said to sharpen intuition and clear the mind.
Traditional beliefs
Not collected yet
Collected Oct 23, 2026
- Comparative Study on Gemological and Mineralogical Characteristics and Coloration Mechanism of Four Color Types of Fluorite (Crystals 13(1): 75, 2023) Liu Y. et al., China University of Geosciences (Beijing), via MDPI Crystals · Accessed Oct 23, 2026 OverviewPropertiesOrigins & sourcesIdentification
- Fluorite (also known as Fluorspar) Geology.com (Hobart M. King, PhD) · Accessed Oct 23, 2026 OverviewProperties
- Fluorite: Mineral information, data and localities Mindat.org (Hudson Institute of Mineralogy) · Accessed Oct 23, 2026 OverviewHistory
- Fluorite Value, Price, and Jewelry Information International Gem Society (Joel E. Arem, Ph.D., FGA) · Accessed Oct 23, 2026 OverviewPropertiesOrigins & sourcesIdentificationCare
- Pascle stone guide: Purple Fluorite Pascle (Japanese retailer; trade claims only) · Accessed Oct 23, 2026 Cultural meanings