2025.2.27 Amethyst sparkles more than you'd expect

Good morning, this is Nori-chan.

Amethyst is the birthstone for February. It is one of the most abundant and easily available minerals, and comes in a variety of colors, from pale and beautiful to deep and milky .

This time, let's take a look at amethyst as a way to kill a few minutes of time.

Amethyst is the birthstone for February . That's why we're focusing on this article and product introduction. As a type of quartz, it has a hardness of 7 and no cleavage. However, from the perspective of someone who creates loose stones, if the stone isn't polished properly, it can develop grooves and unevenness like the surface of a crystal.


Famous production areas include Brazil, Uruguay, Zambia , and many others. There are also several areas in Japan where it can be harvested. Nori-chan has always wanted to try harvesting it herself someday.


The amethyst we sell as a product has a low refractive index and dispersion, but they are so numerous that we often see beautiful crystals. The amethyst below has fingerprint-like inclusions, but is still very beautiful and shines brighter than we expected, considering it's a GemTreeJapan product .


Color change is an optical effect that changes color depending on the type of light that shines on the gemstone. There are types of amethyst that change from purple to red . The image below is an older work from GemTreeJapan. It's hard to call it a color change, so this is just an idea of what it looks like.


In the case of amethyst, purple is a cool color and red is a warm color, so the change between warm and cool colors is called a color change . On the other hand, the change between warm colors or between cool colors (a change in color tone) is called a color shift .

One unique type of amethyst is the milky amethyst we carry in our products. This milky texture is said to be the result of ultra-fine gas/liquid inclusions, rutile, and aluminum . Some, though not all, have an orange luster, like the loose stone below.


Speaking of amethyst, this is what you can find in natural stone shops! Nori-chan had bought one at my parents' house, so I asked my younger brother to take a photo of it.

When you think of amethyst and quartz, you think of geodes . They give the impression of being hollow and filled with crystals. Other minerals can also coexist . The photo above is of a 40kg geode that Nori bought about 10 years ago and left at my parents' house. I forget what the white thing is, but it's not quartz.

This is also part of a geode that Nori-chan bought a long time ago. The large crystals are about 3cm across, and it is possible to cut amethysts this large.

Geodes are formed when minerals contained in boiling water crystallize in cavities created by bubbles/bubbles in lava . It's easy to imagine what they're saying, but when it comes to technical explanations, it seems a bit complicated.

My brother sent me the photo of the geode above, and when I looked at it again, my reaction was, " Has the color faded ?" Amethyst fades . If you place it in a place with strong sunlight, such as a windowsill, the color will fade over time . This one is on a shelf with glass doors in the living room, and it seems to be fading.

There are quite a few minerals that require care when exposed to sunlight. Kunzite and hiddenite are easy examples. Care should be taken with all stones.

We are offering amethyst and chrysoberyl at special prices until February 28th, and if you purchase a single or multiple items worth over 100,000 yen, you will receive one stone free if you add them to your cart, so be sure to take advantage of this opportunity to get your hands on one of GTJ's sparkling pieces.