Specimen at a glance
| Mineral | Quartz (var. amethyst) |
|---|---|
| Chemistry | SiO2 |
| Mohs hardness | 7 |
| Crystal system | Trigonal |
| Form | Lot / parcel |
| You receive | The exact lot pictured |
About this specimen
Four small amethyst cluster plates offered together as a set. Each carries a field of sharp, stubby amethyst points running from pale lavender to deep violet, and each is streaked or capped with a rusty red-brown hematite coating that sits on and just beneath the crystal faces.
That red is iron oxide. Amethyst gets its purple from trace iron locked in the quartz lattice and activated by natural radiation; hematite is the same element in a different role, deposited as its own mineral phase while the pocket was still open. Where hematite was later buried by continued quartz growth it reads as a red phantom frozen inside the crystal; where it settled last it sits on the surface as a dusty film. Several of these show both at once.
The most contrasty piece in the set pairs a deep grape-purple face against a white-grey quartz base, while the others are more evenly hematite-washed across the whole druse.
Amethyst is quartz, Mohs 7. One care note worth taking seriously: amethyst’s colour centre is metastable, and prolonged direct sunlight will bleach it toward grey or brown. Display it out of a sunny window and it holds its colour indefinitely.
No locality label came with these, so none is claimed. Sold as the exact four clusters photographed.
Amethyst: the science
- Take away either ingredient, the iron or the radiation, and the crystal stays colorless. Both are needed for purple.
- Amethyst’s color is heat-sensitive. At roughly 400 to 500 °C it turns yellow or orange, which is how most commercial citrine is made.
- Long exposure to strong sunlight can slowly fade amethyst, so collectors keep their best pieces out of the window.
Go deeper
Want the full story on amethyst: how it forms, how to identify it, and what makes a great specimen?
Questions about this piece
What is amethyst?
Amethyst is purple quartz. Its color comes from trace iron in the crystal combined with natural radiation from the surrounding rock.
How hard is it, and how should I care for it?
It rates 7 on the Mohs scale. Mohs 7. Display away from direct sunlight to protect the color. Rinse in lukewarm water and air dry, and avoid heat.
Is this the exact lot I will receive?
Yes. This lot was photographed as a group, and you receive the pieces shown.
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