Ternesite is a rare calcium silicate sulfate mineral typically found in combustion metamorphic settings or within high-temperature industrial slags. It usually occurs as small, colorless to pale yellow prismatic crystals that can be difficult to distinguish from common sulfates without chemical testing.
Is this ternesite?
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 ternesite with a known reference. Ternesite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ternesite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ternesite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, acicular, granular.
Often confused with
Ternesite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside ternesite
Minerals reported to co-occur with ternesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₅(SiO₄)₂(SO₄)
- Mohs hardness
- 3.5
- Density
- 3.48 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Acicular, Granular
- Cleavage
- Distinct On {010}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Metamorphic Rocks Formed By Combustion of Bituminous Sediments
- Typical price
- $50-300 per specimen
Where rockhounds find ternesite
Classic worldwide localities
- Ettringer Bellerberg, Germany
- Hatrurim Basin, Israel
- Jordansmühl, Poland
Field-hunting tip
Look in metamorphic rocks formed by combustion of bituminous sediments country, the host setting where ternesite typically forms. If you start seeing ettringite, portlandite, afwillite in float, you are in the right ground. Field specimens usually show a prismatic crystals, acicular, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ternesite?+
Where is ternesite found?+
How much is ternesite worth?+
What rocks look like ternesite?+
What minerals are found with ternesite?+
What kind of rock does ternesite form in?+
What is ternesite used for?+
Find ternesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
