Mystery Sphere Revealed – Green Opalised Fluorite

Back in Easter 2026, we decided to have a little fun at The Crystal Tree.

We photographed a beautiful but rather unusual sphere, shared a few clues and asked our customers and followers one simple question:

Can you guess what it is?

The competition has long since closed and our mystery sphere has found its new home, but we decided to keep this post because the answer deserves a little more explanation.

The mystery stone was…

Green Opalised Fluorite

This unusual sphere immediately caught our attention because it doesn’t look like the Fluorite many people are familiar with.

Instead of the more recognisable bands of purple, green and clear Fluorite, this piece had beautiful seafoam-green colouring, creamy swirling patterns and areas of translucency that gave it an almost opal-like appearance.

Hence the name Green Opalised Fluorite.

It’s worth pointing out that this is a trade name, rather than a separate mineral species or a variety of Opal. Names such as these are often used within the crystal trade to describe material with a particularly distinctive appearance.

And this specimen certainly had that!

What is Fluorite?

Fluorite is a mineral composed of calcium fluoride (CaF₂) and is famous for its extraordinary range of colours.

Purple and green are perhaps the colours most commonly associated with Fluorite, but it can also occur in blue, yellow, pink and even colourless crystals. Some specimens contain several colours within a single crystal.

Fluorite commonly forms cubic crystals, although it can develop in other forms too. Its colour, transparency, zoning and inclusions can vary enormously from one locality and specimen to another.

That’s one of the reasons we never tire of seeing it.

Just when you think you know what Fluorite looks like, another piece comes along and surprises you.

The Mystery Sphere Competition

Our original Easter competition asked people to identify the sphere from photographs and clues, and we loved seeing all the different guesses coming in.

Eventually, of course, we revealed our Green Opalised Fluorite and one lucky winner received the sphere itself.

Although the competition is now part of The Crystal Tree’s history, we’ve kept this little Journal post as a reminder of the fun — and because it’s a lovely example of just how varied one mineral can be.

Continue Exploring Earth’s Hidden Treasures

If this unusual Fluorite has sparked your curiosity, visit our Crystal Library to discover more about Fluorite and the many other remarkable minerals that pass through The Crystal Tree.

Sometimes the most interesting specimens are the ones that make us stop and ask:

What on Earth is that?

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Watch the video here:

Mystery Sphere Competition Winner Announced!

We have a winner!

A huge congratulations to Jerry Lindley-Payne who has won this beautiful Mystery Sphere! 🥳