Esseneite is a rare pyroxene group mineral that typically occurs in pyrometamorphic rocks formed by the combustion of organic matter in bituminous sediments. It is most commonly found as microscopic or small grain-like inclusions within complex high-temperature contact metamorphic assemblages. Collectors prize it primarily as a curiosity due to its very restricted type localities and unique geochemical origin.
Is this esseneite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch esseneite with a known reference. Esseneite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Esseneite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Esseneite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, dark brown, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains or small inclusions.
Often confused with
Esseneite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Esseneite leaves white, Augite leaves grayish white.
How to tell apart: Streak differs — Esseneite leaves white, Hedenbergite leaves white to pale green; luster reads vitreous on Esseneite and vitreous to resinous on Hedenbergite.
Often found alongside esseneite
Minerals reported to co-occur with esseneite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaFe³⁺AlSiO₆
- Mohs hardness
- 6
- Density
- 3.32 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to Subhedral Grains or Small Inclusions
- Cleavage
- Good On {110}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- High-temperature, Low-pressure Pyrometamorphic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find esseneite
Classic worldwide localities
- Hatrurim Formation, Israel
- Bellerberg, Germany
- Franklin, New Jersey, USA
Field-hunting tip
Look in high-temperature, low-pressure pyrometamorphic rocks country — that is the host setting where esseneite typically forms. If you start seeing gehlenite, anorthite, rankinite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains or small inclusions habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find esseneite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
