Cerchiaraite-(Fe) is a rare silicate mineral found in manganese-rich metamorphic environments. It typically appears as small, yellowish to brown tabular crystals associated with other manganese minerals like braunite.

Hardness

~4.5

Mohs

Luster

Vitreous

Streak

Colorless to tan or pale green-blue

Transparency

Transparent

mineralrareCerchiaraite Group family

Cerchiaraite-(Fe)

Hardness: ~4.5
Luster: Vitreous
Streak: Colorless to tan or pale green-blue
Transparency: Transparent

Is this cerchiaraite-(fe)?

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 cerchiaraite-(fe) with a known reference. Cerchiaraite-(Fe) 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. Streak: colorless to tan or pale green-blue.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: tan, brown, bluish, bluish green.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: tabular crystals.

Often confused with

Cerchiaraite-(Fe) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Cerchiaraite-(Fe) leaves colorless to tan or pale green-blue, Cerchiaraite-(Mn) leaves pale green.

Compare →

Often found alongside cerchiaraite-(fe)

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

All properties

Chemical formula: Ba₄Fe₄(Si₄O₁₂)O₂(OH)₄Cl₂[Si₂O₃(OH)₄]
Mohs hardness: ~4.5
Density: 3.710 g/cm³
Colors: Tan Brown Bluish Bluish green
Streak: Colorless to tan or pale green-blue
Luster: Vitreous
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Developed in small fractures and veinlets within metacherts of an ophiolitic sequence during prehnite-pumpellyite facies metamorphism

Where rockhounds find cerchiaraite-(fe)

Classic worldwide localities

Cerchiara mine, Borghetto Vara, Vara Valley, La Spezia Province, Liguria, Italy and at the Esquire No. 7 and No. 8 claims, Big Creek, Fresno County, California, USA

Field-hunting tip

Where it forms: Developed in small fractures and veinlets within metacherts of an ophiolitic sequence during prehnite-pumpellyite facies metamorphism. If you start seeing aegirine, calcite, mn-bearing diopside in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cerchiaraite-(fe)?+

Mohs hardness is ~4.5. Luster: vitreous. The streak is colorless to tan or pale green-blue. Common colors include tan, brown, bluish, bluish green.

Where is cerchiaraite-(fe) found?+

Notable localities include Cerchiara mine, Borghetto Vara, Vara Valley, La Spezia Province, Liguria, Italy and at the Esquire No. 7 and No. 8 claims, Big Creek, Fresno County, California, USA.

What rocks look like cerchiaraite-(fe)?+

Cerchiaraite-(Fe) is most often confused with Cerchiaraite-(Mn). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with cerchiaraite-(fe)?+

Cerchiaraite-(Fe) commonly co-occurs with Aegirine, Calcite, Mn-bearing diopside, Hematite, K-feldspar, Norrishite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does cerchiaraite-(fe) form in?+

Where it forms: Developed in small fractures and veinlets within metacherts of an ophiolitic sequence during prehnite-pumpellyite facies metamorphism. Working float back to the host body is the standard way to chase a fresh occurrence.

What is cerchiaraite-(fe) used for?+

Cerchiaraite-(Fe) is used in collector.

Find cerchiaraite-(fe) on the map

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