Loose Tanzanite
One Place on Earth. Far More Than Blue.
Tanzanite from the Merelani Hills of Tanzania
Tanzanite has one origin.
Not one important origin.
One.
Gem-quality tanzanite comes from the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. That incredibly limited geography is part of what made the stone famous after its discovery in the 1960s.
But the reason we keep buying it has much more to do with what happens inside the crystal.
Most people know tanzanite as an intense blue-violet gemstone.
We see something much more complicated.
Teal.
And sometimes several of those colors trying to exist in the same piece of rough.
At Caleb B. Quashen International, we have a particular weakness for unheated Merelani material because it allows you to see a side of this mineral that most people never encounter.
Sometimes it is beautiful.
Sometimes it is strange.
Usually it is both.
What Is Tanzanite?
Tanzanite is the blue-to-violet gem variety of the mineral zoisite.
It was discovered commercially in northern Tanzania in the late 1960s and was named after the country where it was found.
And nowhere else has produced it commercially.
That alone makes the material unusual.
But tanzanite's defining characteristic may be its pleochroism — the ability of a crystal to display different colors when viewed from different directions.
Turn the rough and the color changes.
Change the orientation and the finished gemstone changes.
That makes tanzanite as much a cutter's stone as it is a collector's stone.
One Crystal. Several Colors.
Pleochroism is where tanzanite becomes really interesting.
A single crystal can show dramatically different colors along different crystal directions.
Blue.
Violet.
Purple.
And in unheated material, sometimes green, yellow, brown, or combinations of those tones.
That means two cutters can start with similar rough and end up with gemstones that look completely different simply because of orientation.
One direction may favor blue.
Another may preserve violet.
Another may expose colors that most people have never associated with tanzanite at all.
That is why we spend so much time turning the rough before we decide what to do with it.
The stone is already telling you what is there.
You just have to decide which version you want to keep.
Unheated Tanzanite Is a Different Animal
Most blue and violet tanzanite on the commercial market has been heated.
Heating is generally used to remove or reduce the brown, yellow, and green components that can occur naturally in the rough, leaving the blue and violet colors the market has come to expect.
There is nothing inherently wrong with that.
Heat treatment is accepted and extremely common in tanzanite.
But unheated material gives you something else entirely.
You may see brown mixed with violet.
Green next to blue.
Yellow-green flashes.
Teal.
Purple.
Colors that change as the stone moves.
Sometimes the result does not look like what most people think tanzanite is supposed to look like.
That is usually when we become interested.
A Note About “Fancy-Color Tanzanite”
You may see green, yellow, pink, teal, or other unusual zoisite from Merelani described in the trade as “fancy-color tanzanite.”
We understand why.
It comes from the same extraordinary deposit and is closely related to the blue-violet material everyone recognizes as tanzanite.
Gemologically, however, there is an important distinction.
The name tanzanite is traditionally applied to blue-to-violet gem zoisite. Material that remains green, yellow, pink, or another color may more precisely be described simply as zoisite.
We would rather explain the distinction than pretend it does not exist.
Whatever name is used, the unusual unheated material coming out of Merelani can be extraordinary.
And we collect quite a bit of it.
Why Most Tanzanite Looks Blue
There is a reason the jewelry market is dominated by blue and violet tanzanite.
That is what consumers learned to expect.
Heating often brings those colors forward, and cutters can orient the rough to emphasize either blue or violet depending on the crystal and how much weight they are willing to sacrifice.
A blue face-up stone may require a very different orientation from a violet one.
Sometimes obtaining the strongest blue means cutting away substantially more rough.
That makes orientation an economic decision as much as an artistic one.
We try to start with a different question.
What is the best version of this particular crystal?
Sometimes it is blue.
Sometimes it very clearly is not.
Cutting Tanzanite
Tanzanite can punish a lazy cutting decision.
Because the material is strongly pleochroic, orientation changes everything.
Color.
Saturation.
Face-up appearance.
Weight.
Even the overall mood of the finished stone.
A piece of rough that looks brownish from one direction might show violet from another.
Rotate it again and green may appear.
So before a facet ever touches the wheel, we spend time looking.
Where is the blue?
Where is the violet?
What happens to the green?
Is there zoning worth keeping?
Are we willing to lose weight to get a different face-up color?
Or is the strange direction actually the better stone?
There is no universal answer.
That is what makes cutting it fun.
Precision Cuts, Geometric Shapes & Unusual Rough
Most commercial tanzanite is cut into familiar shapes.
Those shapes work for a reason.
But clean zoisite crystals can also give cutters room to do something more interesting.
Elongated forms.
Cuts designed around the actual crystal rather than a standardized diagram.
We like letting the rough influence that decision.
If the crystal is telling us to make an oval, fine.
If it is telling us something much stranger, even better.
Tanzanite Color & Value
The traditional tanzanite market places the highest value on deeply saturated blue-violet and violet-blue stones.
Color saturation matters.
Size matters too.
Larger tanzanites are often capable of displaying stronger color than smaller stones, which is one reason large, richly saturated examples can command significant premiums.
But market value and personal interest are not always the same thing.
A textbook blue-violet tanzanite may be commercially more valuable.
An unheated stone showing green, gold, violet, and blue may be far more difficult to replace.
We believe both deserve a place in the conversation.
Clarity
Fine faceted tanzanite is often relatively clean.
That means visible inclusions tend to stand out more than they might in a gemstone where inclusions are expected.
Fractures are especially important because tanzanite requires more care than sapphire or diamond.
But again, we look at the actual stone.
An inclusion that affects durability is one thing.
A minor internal feature that gives an unusual piece of material personality is another.
Those are not the same conversation.
Tanzanite Is Not Sapphire
This sounds obvious to gemstone people.
It is not obvious to everyone shopping for a blue gemstone.
Tanzanite and sapphire can overlap visually in the blue-violet range, but they are completely different minerals.
Sapphire is corundum.
Tanzanite is zoisite.
Sapphire is considerably harder and tougher for everyday wear.
Tanzanite offers stronger pleochroism and a color experience that sapphire simply does not replicate.
Neither needs to replace the other.
They do different things.
Is Tanzanite Rare?
Tanzanite has an exceptionally restricted source.
Commercial tanzanite production comes from one relatively small mining area in the Merelani Hills of Tanzania.
That does not mean every tanzanite is automatically rare or valuable.
Quality still matters.
Color.
Clarity.
Size.
Cut.
Treatment.
And the individual stone.
But when you compare its geographic occurrence with gemstones mined across entire continents, the source is remarkably limited.
There simply is not another Merelani.
Choosing a Loose Tanzanite
This is a gemstone we strongly prefer choosing loose.
You need to see the color.
You need to see the orientation.
You need to see what happens when the stone moves.
A photograph from one direction can completely miss part of the story.
An intensely blue stone may feel entirely different from a violet one.
An unheated green-blue piece may dictate the entire design.
A geometric cut may need a setting built specifically around its proportions.
Start with the stone.
Look at it in different light.
Turn it.
Then figure out what it should become.
Tanzanite in Custom Jewelry
Tanzanite can make extraordinary jewelry, but the design needs to respect the material.
It has a Mohs hardness of roughly 6 to 7 and does not have the toughness of sapphire or diamond.
That does not mean you cannot put it in a ring.
It means you should think about how the ring will be worn.
Protective settings can help reduce exposure to hard impacts, and earrings, pendants, and occasion rings can be excellent ways to use particularly unusual stones.
The setting should be designed around the gemstone.
Not the other way around.
Why We Keep Buying Tanzanite
We already know what perfect commercial tanzanite looks like.
Deep blue.
Strong violet.
Clean.
Beautiful.
We like that material.
But it is not the only thing we are looking for.
We want the crystal that still carries green.
The stone with violet moving through brown.
The teal piece someone else might heat because that is what the market expects.
The rough that changes completely when you rotate it.
The strange one.
The difficult one.
The one where the cutter has to make an actual decision.
Tanzanite only comes from one place.
We do not see much reason to make all of it look the same.
Tanzanite Questions
Where does tanzanite come from?
Tanzanite comes from the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. It is the only commercial source of tanzanite in the world.
Is tanzanite always blue?
No.
The blue-to-violet material is what is traditionally called tanzanite, but natural zoisite from the Merelani deposit can display brown, green, yellow, violet, blue, and other colors before treatment.
Strong pleochroism can also make the same crystal show different colors depending on viewing direction.
Is most tanzanite heated?
Yes.
Most commercial blue-violet tanzanite has been heat treated. Heating commonly reduces brown, green, and yellow tones and reveals the blue and violet colors consumers typically associate with tanzanite.
Is unheated tanzanite rare?
Unheated material showing attractive natural color can be unusual, particularly when it displays strong blue, violet, green, or multicolor pleochroism without treatment.
We are especially interested in unheated material because it preserves more of the crystal's original color story.
What is pleochroism in tanzanite?
Pleochroism is the ability of the gemstone to display different colors when viewed along different crystal directions.
Tanzanite is particularly famous for this effect, which is why cutting orientation has such a dramatic influence on the finished stone.
Why do some tanzanites look greener than others?
Green, yellow, and brown components can naturally occur in unheated zoisite from Merelani.
Heating commonly reduces those colors, which is why greenish material is far less familiar to most consumers.
Is green tanzanite really tanzanite?
In the trade, green and other unusual colors from Merelani are sometimes referred to as fancy-color tanzanite.
Gemologically, laboratories such as GIA generally reserve the name tanzanite for blue-to-violet zoisite and identify other colors simply as zoisite.
Is tanzanite good for an engagement ring?
It can be used in an engagement ring, but it needs more care than sapphire or diamond.
Tanzanite has a hardness of roughly 6 to 7 and can be vulnerable to hard impacts. A protective setting and thoughtful wearing habits are especially important for an everyday ring.
What color tanzanite is most valuable?
Traditionally, deeply saturated blue-violet or violet-blue tanzanite commands the strongest market prices, particularly in larger, clean stones.
Unusual unheated material can appeal to a very different type of collector, where rarity of color and overall character may matter more than conventional grading preferences.
Can CBQ source a specific tanzanite?
Yes.
We work extensively with tanzanite and unheated zoisite from the Merelani region. If you are looking for a particular size, color, treatment status, cut, or unusual color combination, contact us and tell us what you are trying to find.