Metadelrioite is an extremely rare vanadium mineral typically found as small, yellow, transparent crystals. It is chemically related to delrioite and occurs primarily in oxidized zones of uranium-vanadium deposits in sandstone.

Hardness

Mohs

Luster

Vitreous to pearly

Streak

Pale yellow green

Transparency

Translucent

mineralrare

Metadelrioite

Hardness: ~2
Luster: Vitreous to pearly
Streak: Pale yellow green
Transparency: Translucent

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Is this metadelrioite?

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 metadelrioite with a known reference. Metadelrioite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pale yellow green.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to pearly.
4
Match the color range
Compare against the expected color range: pale yellow green.
5
Look at form & habit
Crystal system: triclinic. Typical habit: fibrous.

Often confused with

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

How to tell apart: Streak differs, so Metadelrioite leaves pale yellow green, Carnotite leaves strontian-yellow; luster reads vitreous to pearly on Metadelrioite and dull, earthy; silky when crystalline on Carnotite.

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Often found alongside metadelrioite

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

All properties

Chemical formula: SrCa(VO₃)₂(OH)₂
Mohs hardness: ~2
Density: 4.3 g/cm³
Colors: Pale yellow green
Streak: Pale yellow green
Luster: Vitreous to pearly
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Fibrous
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: An efflorescence on sandstone of the Salt Wash member of the Jurassic Morrison Formation associated with a U–V deposit

Where rockhounds find metadelrioite

Classic worldwide localities

Jo Dandy mine, Montrose County, Colorado, USA (type locality)

Field-hunting tip

Where it forms: An efflorescence on sandstone of the Salt Wash member of the Jurassic Morrison Formation associated with a U–V deposit. If you start seeing delrioite, rossite, metarossite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify metadelrioite?+

Mohs hardness is ~2. Luster: vitreous to pearly. The streak is pale yellow green. Common colors include pale yellow green.

Where is metadelrioite found?+

Notable localities include Jo Dandy mine, Montrose County, Colorado, USA (type locality).

Is metadelrioite safe to handle?+

Metadelrioite contains vanadium. Contains vanadium, which can be toxic if ingested or inhaled as dust; wash hands thoroughly after handling.

What rocks look like metadelrioite?+

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

What minerals are found with metadelrioite?+

Metadelrioite commonly co-occurs with Delrioite, Rossite, Metarossite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does metadelrioite form in?+

Where it forms: An efflorescence on sandstone of the Salt Wash member of the Jurassic Morrison Formation associated with a U–V deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is metadelrioite used for?+

Metadelrioite is used in collector.

Find metadelrioite on the map

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