Kratochvílite is a rare organic mineral belonging to the hydrocarbon group, typically forming within burning coal seams. It is most easily identified by its distinct blue fluorescence under ultraviolet light and its low density, often appearing as pale, waxy tabular crystals or crusts.

Hardness
1
Mohs
Luster
Resinous
Streak
White
Transparency
Transparent

Is this kratochvílite?

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 kratochvílite with a known reference. Kratochvílite sits at Mohs 1 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Kratochvílite leaves a white streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Kratochvílite typically shows a resinous luster.
  • 4
    Match the color range
    Compare against the expected color range: yellow, colorless, white.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: tabular crystals, massive, incrustations.

Often confused with

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

Often found alongside kratochvílite

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

All properties

Chemical formula
C₁₄H₁₀
Mohs hardness
1
Density
1.10 g/cm³
Streak
White
Luster
Resinous
Transparency
Transparent
Crystal system
Orthorhombic
Crystal habit
Tabular Crystals, Massive, Incrustations
Cleavage
None
Fluorescence
Bright Blue Under UV
Rarity
Rare
Uses
Collector
Host rock
Coal Seams
Typical price
$20-150 thumbnail

Where rockhounds find kratochvílite

Classic worldwide localities

  • Czech Republic
  • Germany

Field-hunting tip

Look in coal seams country — that is the host setting where kratochvílite typically forms. If you start seeing coal, carbonaceous shale in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, incrustations habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kratochvílite?+
Mohs hardness is 1. It typically shows a resinous luster. The streak is white. Common colors include yellow, colorless, white.
Where is kratochvílite found?+
Notable localities include Czech Republic; Germany.
How much is kratochvílite worth?+
Typical asking prices fall in the range of $20-150 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.
What rocks look like kratochvílite?+
Kratochvílite is most often confused with Sulfur. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with kratochvílite?+
Kratochvílite commonly co-occurs with Coal, Carbonaceous shale. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does kratochvílite form in?+
Kratochvílite typically forms in coal seams. Working float back to the host body is the standard way to chase a fresh occurrence.
What is kratochvílite used for?+
Kratochvílite is used in collector.

Find kratochvílite on the map

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