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

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Defernite

Hardness: 3-4
Luster: Vitreous
Streak: White
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 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Defernite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Defernite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale gray.
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.

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)₂(OH,Cl)₆
Mohs hardness: 3-4
Density: 2.85 g/cm³
Colors: Colorless White Pale Gray
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Massive, Granular Aggregates
Cleavage: Distinct On {010}
Rarity: Rare
Uses: Collector
Host rock: Metasomatized Carbonate Rocks
Typical price: $20-100 per specimen

Where rockhounds find defernite

Classic worldwide localities

Urals, Russia
Kola Peninsula, Russia

Field-hunting tip

Look in metasomatized carbonate rocks country — that is the host setting where defernite typically forms. If you start seeing calcite, hydrotalcite, tobermorite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify defernite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, pale gray.

Where is defernite found?+

Notable localities include Urals, Russia; Kola Peninsula, Russia.

How much is defernite worth?+

Typical asking prices fall in the range of $20-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

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 Calcite, Hydrotalcite, Tobermorite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does defernite form in?+

Defernite typically forms in metasomatized carbonate rocks. 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.