Hydropyrochlore is a rare member of the pyrochlore group characterized by significant vacancy in the A-site of its crystal structure and high water content. It typically forms sharp, lustrous octahedral crystals in alkaline igneous environments like carbonatites. Due to its radioactive nature, it is primarily a target for advanced systematic mineral collectors.

Hardness

5-5.5

Mohs

Luster

Vitreous

Streak

Light Yellow

Transparency

Translucent

mineralrarePyrochlore Group family

Hydropyrochlore

Hardness: 5-5.5
Luster: Vitreous
Streak: Light Yellow
Transparency: Translucent

Is this hydropyrochlore?

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 hydropyrochlore with a known reference. Hydropyrochlore sits at Mohs 5-5.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Hydropyrochlore leaves a light yellow streak.
3
Read the luster
Hold the specimen under a strong light. Hydropyrochlore typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: brown, yellowish-brown, reddish-brown.
5
Look at form & habit
Crystal system: cubic. Typical habit: octahedral.

Often found alongside hydropyrochlore

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

All properties

Chemical formula: (H₂O,□)₂Nb₂O₆(OH,F)
Mohs hardness: 5-5.5
Density: 4.2-4.8 g/cm³
Colors: Brown Yellowish-brown Reddish-brown
Streak: Light Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Cubic
Crystal habit: Octahedral
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Carbonatites
Typical price: $20-150 thumbnail

Where rockhounds find hydropyrochlore

Classic worldwide localities

Lueshe Carbonatite, Democratic Republic of the Congo
Araxa, Brazil
Kola Peninsula, Russia

Field-hunting tip

Look in carbonatites country, the host setting where hydropyrochlore typically forms. If you start seeing calcite, aegirine, biotite in float, you are in the right ground. Field specimens usually show a octahedral habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify hydropyrochlore?+

Mohs hardness is 5-5.5. It typically shows a vitreous luster. The streak is light yellow. Common colors include brown, yellowish-brown, reddish-brown.

Where is hydropyrochlore found?+

Notable localities include Lueshe Carbonatite, Democratic Republic of the Congo; Araxa, Brazil; Kola Peninsula, Russia.

How much is hydropyrochlore worth?+

Typical asking prices fall in the range of $20-150 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is hydropyrochlore safe to handle?+

This mineral is radioactive. Contains radioactive elements; store away from other minerals, handle with gloves, and wash hands thoroughly after handling. Do not ingest or inhale dust. Handle with care, avoid grinding or breathing dust, and store separately.

What minerals are found with hydropyrochlore?+

Hydropyrochlore commonly co-occurs with Calcite, Aegirine, Biotite, Fluorapatite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does hydropyrochlore form in?+

Hydropyrochlore typically forms in carbonatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is hydropyrochlore used for?+

Hydropyrochlore is used in collector.

Find hydropyrochlore on the map

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