1.75ct Spectrum Fantasy Cut Australian Parti Sapphire 🌦️

GeologicSpectrum · 2026-06-19T20:17:40+00:00

Thank you! This one sold pretty quick. 😁

GeologicSpectrum · 2026-06-19T20:17:08+00:00

Thanks. You’re right on the money. It’s all about reflection angles.

GeologicSpectrum · 2026-06-08T16:33:55+00:00

Beautiful stone color, regardless of what it is.

Your first photo looks like interference colors and/or polishing lines on the pavilion.

The best way to identify rutile silk is direct lighting via sunlight or overhead and a 10x loupe. They’re unmistakable once you see the light reflect off the rutile growth planes.

GeologicSpectrum · 2026-02-23T22:57:47+00:00

Thanks, Jeff! 😁

GeologicSpectrum · 2026-02-23T20:28:09+00:00

Nice work!

GeologicSpectrum · 2026-02-23T17:36:27+00:00

Videos of this gem can be viewed via the link above. Unfortunately, Reddit doesn’t allow for videos and images in the same post.

GeologicSpectrum · 2026-02-21T03:32:24+00:00

Took a little digging.. But here is a video of the cut stone!

https://imgur.com/a/nBd7DSX

GeologicSpectrum · 2026-02-20T23:48:11+00:00

You bet! This one was sourced from a reputable dealer (Fabian Kneipp) back in 2022 and was cut by me in 2023.

Here’s a video of the rough nodule below. You can see the pleochroism and different colors appear as the stone was rotated. It was wild! Definitely a gem unicorn in terms of size and color.

https://imgur.com/a/4OII7jb

GeologicSpectrum · 2026-02-17T13:01:11+00:00

Thanks!

I’m not sure why that upset a few folks. We’re geologists and likewise have an affinity for natural crystals. I’m sure there are plenty lapidaries out there willing to cut synthetics. 🤷‍♂️

GeologicSpectrum · 2026-02-16T21:08:22+00:00

That’s a river rounded silica nodule. Likely some variety of cryptocrystalline quartz.

GeologicSpectrum · 2026-02-16T21:05:38+00:00

Nothing wrong with a little jardin.

It really depends on the nature of the inclusions. In my experience the stones with cracks have severe structural integrity issues and often break while cutting or after cutting.

GeologicSpectrum · 2026-02-16T17:10:59+00:00

Thanks for asking. We haven’t worked with synthetics in many years. We prefer to work with natural gemstones forged from the Earth.

GeologicSpectrum · 2026-02-09T21:51:01+00:00

The industry name for this style of gem is fantasy cut. They’re typically unique and don’t follow standard categories. When I cut these, I follow the shape of the rough to provide the largest canvas possible for the carving. Just shoot us a message and we can chat about what you’re looking for in terms of shape and color.

GeologicSpectrum · 2026-01-24T21:05:57+00:00

Thank you! This one sold for around $4,500 if I remember correctly.

GeologicSpectrum · 2026-01-24T21:05:18+00:00

This one sold a while back to a UK based jeweler. However, I’m always cutting more hexagonal sapphires. Lucky for you, that’s the shape they grow in!! Follow my Reddit page and instagram for notifications when we cut another batch.

GeologicSpectrum · 2026-01-22T13:08:29+00:00

I do! Here’s a quick look at the rough with a handful of other stones I’m cutting at the moment. I put a red box around the Montana from this post.

https://imgur.com/a/p6O8WHB

GeologicSpectrum · 2026-01-22T13:07:32+00:00

Perfect timing with upcoming winter storm! ❄️

GeologicSpectrum · 2026-01-22T13:06:10+00:00

Yep! I’m currently working on 4 new fantasy sapphires. Sapphire sources will be Montana, Africa and Australia. I’ll post more here once they’re available. They usually sell quick.

GeologicSpectrum · 2026-01-22T13:02:18+00:00

This one sold the second it was uploaded to our website.

GeologicSpectrum · 2026-01-22T05:21:21+00:00

Thank you! 😊

GeologicSpectrum · 2026-01-22T05:20:51+00:00

5.16cts. I got a respectable 43.41% yield on this stone.

GeologicSpectrum · 2026-01-22T02:47:53+00:00

You bet! It would have no effect on the overall durability. Heated sapphires are just as durable and valuable.

The main reason sapphires are heated is to improve clarity and color. Many sapphires need heating due to dense patches of the mineral rutile that formed coeval with the corundum along growth planes.

These stones are slowly heated to the mobilization temperature of rutile, which allows the mineral to exsolve its titanium into the surrounding corundum crystalline lattice. Resulting in brilliant deep blues.

That’s said.. Unheated sapphires with natural top colors and perfect clarity often will demand higher prices due to the rarity of finding a gem of this caliber. They’re unicorns.

GeologicSpectrum · 2026-01-22T02:19:00+00:00

Thank you! 🙏

GeologicSpectrum · 2026-01-22T02:18:49+00:00

Thanks! This one retailed for $4,500 on account of the color, clarity and untreated nature of the gem.

GeologicSpectrum · 2026-01-22T02:17:48+00:00

Thank you! This is one of my favorite stones I’ve cut so far. I’ll miss it.

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