Lopatkaite is a rare lead antimony arsenic sulfosalt. It was approved as a distinct mineral species in 2012. It was first described from Madoc, Ontario, Canada.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

Yellowish

Transparency

Transparent

mineralrare

Lopatkaite

Lopatkaite is a rare lead antimony arsenic sulfosalt. It was approved as a distinct mineral species in 2012. It was first described from Madoc, Ontario, Canada.

Hardness: 3.5-4
Luster: Vitreous
Streak: Yellowish
Transparency: Transparent

No image

Is this lopatkaite?

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 lopatkaite with a known reference. Lopatkaite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: yellowish.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: yellow, yellow-brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Labuntsovite

Mohs 6

How to tell apart: Labuntsovite is the harder of the two (Mohs 6 vs. 3.5-4); streak differs, so Lopatkaite leaves yellowish, Labuntsovite leaves white; luster reads vitreous on Lopatkaite and greasy on Labuntsovite.

How to tell apart: Nenadkevichite is the harder of the two (Mohs 5 vs. 3.5-4); streak differs, so Lopatkaite leaves yellowish, Nenadkevichite leaves white to very pale rose.

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Often found alongside lopatkaite

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

All properties

Chemical formula: Pb₅Sb₃AsS₁₁
Mohs hardness: 3.5-4
Density: 4.57 g/cm³
Colors: Yellow Yellow-brown
Streak: Yellowish
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: alkaline igneous rocks

Where rockhounds find lopatkaite

Classic worldwide localities

Madoc, Ontario, Canada

Field-hunting tip

Where it forms: alkaline igneous rocks. If you start seeing aegirine, microcline, nepheline 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 lopatkaite?+

Mohs hardness is 3.5-4. Luster: vitreous. The streak is yellowish. Common colors include yellow, yellow-brown.

Where is lopatkaite found?+

Notable localities include Madoc, Ontario, Canada.

Is lopatkaite safe to handle?+

Lopatkaite contains antimony, arsenic and lead and calls for real care. Contains antimony, arsenic and lead, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust.

What rocks look like lopatkaite?+

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

What minerals are found with lopatkaite?+

Lopatkaite commonly co-occurs with Aegirine, Microcline, Nepheline, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lopatkaite form in?+

Where it forms: alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is lopatkaite used for?+

Lopatkaite is used in collector.

Find lopatkaite on the map

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