Tvrdýite is a rare aluminum phosphate mineral related to variscite, typically found as attractive botryoidal crusts or nodules within phosphate-rich sedimentary sequences. Collectors value it for its vibrant green hues and distinctive waxy luster when found in high-quality cabinet specimens.

Hardness

4-5

Mohs

Luster

Waxy

Streak

White

Transparency

Translucent

mineralrareVariscite Group family

Tvrdýite

Hardness: 4-5
Luster: Waxy
Streak: White
Transparency: Translucent

Is this tvrdýite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch tvrdýite with a known reference. Tvrdýite sits at Mohs 4-5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tvrdýite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Tvrdýite typically shows a waxy luster.
4
Match the color range
Compare against the expected color range: green, yellow-green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: botryoidal, crusts, massive.

Often confused with

Tvrdýite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads waxy on Tvrdýite and vitreous on Wardite.

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Often found alongside tvrdýite

Minerals reported to co-occur with tvrdýite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: AlPO₄·2H₂O
Mohs hardness: 4-5
Density: 2.5-2.6 g/cm³
Colors: Green Yellow-green
Streak: White
Luster: Waxy
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Botryoidal, Crusts, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Phosphate Nodules in Sedimentary Rocks
Typical price: $20-100 per specimen

Where rockhounds find tvrdýite

Classic worldwide localities

Czech Republic
Germany

Field-hunting tip

Look in phosphate nodules in sedimentary rocks country, the host setting where tvrdýite typically forms. If you start seeing variscite, crandallite, goyazite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tvrdýite?+

Mohs hardness is 4-5. It typically shows a waxy luster. The streak is white. Common colors include green, yellow-green.

Where is tvrdýite found?+

Notable localities include Czech Republic; Germany.

How much is tvrdýite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like tvrdýite?+

Tvrdýite is most often confused with Variscite, Wardite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tvrdýite?+

Tvrdýite commonly co-occurs with Variscite, Crandallite, Goyazite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tvrdýite form in?+

Tvrdýite typically forms in phosphate nodules in sedimentary rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tvrdýite used for?+

Tvrdýite is used in collector.

Find tvrdýite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.