Amethyst â Properties, Hardness, and Fluorescence
Amethyst is one of the most well-known and valued crystals in the quartz group. It is recognized by its purple hue, which can range from light lavender to deep, dark violet.
Amethyst is especially known for its associations with calmness, balance, and mental clarity, but it is also an interesting stone due to its gemmological properties.
What is amethyst?
Amethyst belongs to the quartz group, and its chemical composition is silicon dioxide, or SiOâ. The same mineral family also includes, for example, rock crystal, smoky quartz, rose quartz, and citrine.
Amethyst's purple color is caused by the presence of iron in the crystal's structure. The shade can vary depending on how much iron is present in the crystal and under what conditions the stone was formed.
Read more about the meaning of amethyst
Hardness of amethyst
Amethyst has a hardness of 7 on the Mohs scale, which makes it a relatively durable crystal for everyday use and jewelry.
The Mohs hardness scale measures the scratch resistance of minerals. For comparison:
- Fingernail hardness is about 2.5
- Steel hardness is about 5â6
- Diamond hardness is 10
Amethyst tolerates ordinary use well, but it should still be handled carefully to keep its surface clean and shiny.
Does amethyst fluoresce?
Amethyst can exhibit weak fluorescence under ultraviolet light. Some amethysts show a bluish or pale glow under UV light, but fluorescence is usually quite minor.
Not all amethysts fluoresce in the same way, as the phenomenon depends on the crystal's composition and impurities.
Fluorescence means that a mineral reacts to UV light by visibly glowing.
Amethyst structure and appearance
Amethyst often forms as hexagonal crystals that grow in clusters, for example, inside geodes.
The crystal can be:
- translucent
- completely transparent
- raw
- polished
- banded, like chevron amethyst
Where is amethyst found?
Amethyst is found in many different countries around the world. The most well-known deposits include:
- Brazil
- Uruguay
- Zambia
- Madagascar
- India
Brazil and Uruguay, in particular, are known for their spectacular amethyst clusters and geodes.
Can amethyst change color?
Yes. Prolonged direct sunlight can fade amethyst's purple hue over time.
Intense heating can also change the color of amethyst. Some citrines are actually heat-treated amethyst whose color has turned yellow or golden-brown.
Amethyst use in jewelry and decor
Thanks to its good hardness, amethyst is well suited for:
- jewelry
- decorative stones
- collecting
- pocket stones
- bedroom and nightstand decor
Amethyst is also a popular gift stone, as its purple hue and crystalline structure look impressive in many types of decor.
See crystals for sleep and relaxation
How to care for amethyst?
Amethyst should be cleaned with a soft cloth and stored away from prolonged direct sunlight.
Although amethyst is a fairly durable crystal, it should not be stored where it constantly rubs against other stones.
Frequently asked questions about amethyst properties
What is the hardness of amethyst?
Amethyst has a hardness of 7 on the Mohs scale.
Does amethyst fluoresce under UV light?
Some amethysts show a weak bluish fluorescence under UV light.
What causes the purple color of amethyst?
The color is primarily caused by the presence of iron in the crystal's structure.
Is amethyst real quartz?
Yes. Amethyst belongs to the quartz group, and its chemical composition is SiOâ.
Summary
Amethyst is a purple crystal belonging to the quartz group, with a hardness of 7 on the Mohs scale. It is known for both its striking appearance and its associations with calmness and balance.
Amethyst's properties include good durability, a hexagonal crystal structure, and in some cases, weak fluorescence under UV light.