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, so Sincosite leaves pale green, Roscoelite leaves light green.

How to tell apart: Streak differs, so 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, 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.