Sincosite is a rare vanadium phosphate mineral typically found as small, bright green, platy crystals. It is most often found in association with vanadium-bearing sedimentary rocks where it forms thin crusts or micaceous coatings on host rock surfaces.

Hardness

Mohs

Luster

Pearly

Streak

Pale Green

Transparency

Translucent

mineralrare

Sincosite

Hardness: 2
Luster: Pearly
Streak: Pale Green
Transparency: Translucent

Is this sincosite?

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 sincosite with a known reference. Sincosite 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. Sincosite leaves a pale green streak.
3
Read the luster
Hold the specimen under a strong light. Sincosite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: bright green, olive green.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: platy crystals, micaceous aggregates.

Often confused with

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

mineral

Roscoelite

Mohs 2.5-3

How to tell apart: Streak differs — Sincosite leaves pale green, Roscoelite leaves light green.

How to tell apart: Streak differs — Sincosite leaves pale green, Tyuyamunite leaves yellow.

Compare →

Often found alongside sincosite

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

All properties

Chemical formula: CaV₂O₆·4H₂O
Mohs hardness: 2
Density: 2.88 g/cm³
Colors: Bright Green Olive Green
Streak: Pale Green
Luster: Pearly
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals, Micaceous Aggregates
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Sedimentary Shale and Sandstone
Typical price: $50-300 per specimen

Where rockhounds find sincosite

Classic worldwide localities

Sincos, Peru
Utah, USA
Colorado, USA

Field-hunting tip

Look in sedimentary shale and sandstone country — that is the host setting where sincosite typically forms. If you start seeing gypsum, calcite, quartz in float, you are in the right ground. Field specimens usually show a platy crystals, micaceous aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sincosite?+

Mohs hardness is 2. It typically shows a pearly luster. The streak is pale green. Common colors include bright green, olive green.

Where is sincosite found?+

Notable localities include Sincos, Peru; Utah, USA; Colorado, USA.

How much is sincosite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is sincosite safe to handle?+

It contains toxic constituents. Contains vanadium; avoid inhalation of dust and wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like sincosite?+

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

What minerals are found with sincosite?+

Sincosite commonly co-occurs with gypsum, calcite, quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sincosite form in?+

Sincosite typically forms in sedimentary shale and sandstone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sincosite used for?+

Sincosite is used in collector.

Find sincosite on the map

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