Minrecordite is a rare zinc-dominant member of the dolomite group, often found as small, sharp rhombohedral crystals in the oxidized zones of metal mines. It is visually indistinguishable from dolomite to the naked eye, requiring chemical analysis for positive identification. It is most famously collected from the Tsumeb Mine in Namibia, where it occurs alongside other rare zinc secondary minerals.

Hardness

3.5

Mohs

Luster

Vitreous to pearly

Streak

White

Transparency

Semitransparent

mineralrareDolomite Group family

Minrecordite

Hardness: 3.5
Luster: Vitreous to pearly
Streak: White
Transparency: Semitransparent

Is this minrecordite?

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 minrecordite with a known reference. Minrecordite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to pearly.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: trigonal. Typical habit: rhombohedral crystals.

Often confused with

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

Often found alongside minrecordite

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

All properties

Chemical formula: CaZn(CO₃)₂
Mohs hardness: 3.5
Density: 3.45 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous to pearly
Transparency: Semitransparent
Crystal system: Trigonal
Crystal habit: Rhombohedral crystals
Cleavage: On {1014}, prominent
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia); from the wallrock of a carbonate-hosted Pb–Zn orebody (Navan deposit, Ireland)

Where rockhounds find minrecordite

Classic worldwide localities

Centennial Eureka mine, Tintic district, Juab Co., Utah, USA
Tsumeb, Namibia
Navan Pb–Zn orebody, Co. Meath, Ireland

Field-hunting tip

Where it forms: In a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia); from the wallrock of a carbonate-hosted Pb–Zn orebody (Navan deposit, Ireland). If you start seeing dioptase, duftite, malachite in float, you are in the right ground. Typical habit: rhombohedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify minrecordite?+

Mohs hardness is 3.5. Luster: vitreous to pearly. The streak is white. Common colors include colorless, white.

Where is minrecordite found?+

Notable localities include Centennial Eureka mine, Tintic district, Juab Co., Utah, USA; Tsumeb, Namibia; Navan Pb–Zn orebody, Co. Meath, Ireland.

What rocks look like minrecordite?+

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

What minerals are found with minrecordite?+

Minrecordite commonly co-occurs with Dioptase, Duftite, Malachite, Cerussite, Zincian dolomite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does minrecordite form in?+

Where it forms: In a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia); from the wallrock of a carbonate-hosted Pb–Zn orebody (Navan deposit, Ireland). Working float back to the host body is the standard way to chase a fresh occurrence.

What is minrecordite used for?+

Minrecordite is used in collector, scientific research.

Find minrecordite on the map

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