Defernite is a rare carbonate mineral typically found in metamorphic environments associated with contact metasomatism. It often appears as small, tabular crystals or as granular masses, and is primarily prized by advanced mineral collectors due to its scarcity.

Hardness

Mohs

Luster

Vitreous

Streak

Pink

Transparency

Transparent

mineralrare

Defernite

Hardness: 3
Luster: Vitreous
Streak: Pink
Transparency: Transparent

Is this defernite?

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 defernite with a known reference. Defernite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pink.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, reddish brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, massive, granular aggregates.

Often confused with

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

mineral

Calcite

Mohs 3

How to tell apart: Streak differs, so Defernite leaves pink, Calcite leaves white.

How to tell apart: Streak differs, so Defernite leaves pink, Aragonite leaves white.

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Often found alongside defernite

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

All properties

Chemical formula: Ca₆(CO₃)₁.₅₈(Si₂O₇)₀.₂₁(OH)₇[Cl₀.₅₀(OH)₀.₀₈(H₂O)₀.₄₂]
Mohs hardness: 3
Density: 2.34-2.5 g/cm³
Colors: Colorless Reddish brown
Streak: Pink
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, massive, granular aggregates
Cleavage: Perfect on {010}; distinct on {100}
Rarity: Rare
Uses: Collector
Host rock: In skarn at a granite-limestone contact (Güneyce-_ Ikizdere, Turkey); throughout a body of unbanded, granular massive hausmannite (Kombat mine, Namibia)

Where rockhounds find defernite

Classic worldwide localities

Güneyce-_ Ikizdere area, Trabzon Province, Turkey
Kombat mine, 49 km south of Tsumeb, Namibia

Field-hunting tip

Where it forms: In skarn at a granite-limestone contact (Güneyce-_ Ikizdere, Turkey); throughout a body of unbanded, granular massive hausmannite (Kombat mine, Namibia). If you start seeing vesuvianite, wollastonite, andradite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify defernite?+

Mohs hardness is 3. Luster: vitreous. The streak is pink. Common colors include colorless, reddish brown.

Where is defernite found?+

Notable localities include Güneyce-_ Ikizdere area, Trabzon Province, Turkey; Kombat mine, 49 km south of Tsumeb, Namibia.

What rocks look like defernite?+

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

What minerals are found with defernite?+

Defernite commonly co-occurs with Vesuvianite, Wollastonite, Andradite, Diopside, Calcite, Rustumite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does defernite form in?+

Where it forms: In skarn at a granite-limestone contact (Güneyce-_ Ikizdere, Turkey); throughout a body of unbanded, granular massive hausmannite (Kombat mine, Namibia). Working float back to the host body is the standard way to chase a fresh occurrence.

What is defernite used for?+

Defernite is used in collector.

Find defernite on the map

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