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.

Compare →

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 — that is 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.