Eulytine is a rare bismuth silicate mineral typically found in hydrothermal veins associated with bismuth ores. It is most recognized for its distinct tetrahedral crystal habit and high luster, appearing in shades of yellow to brownish-grey.
Is this eulytine?
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 eulytine with a known reference. Eulytine sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white or yellowish gray.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous or adamantine.
- 4Match the color rangeCompare against the expected color range: dark brown, yellowish gray, grayish white, straw-yellow, colorless.
- 5Look at form & habitCrystal system: cubic. Typical habit: tetrahedral crystals, rounded dodecahedrons, massive.
Often confused with
Eulytine vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Eulytine leaves white or yellowish gray, Sphalerite leaves pale brown to pale yellow and white.
How to tell apart: Luster reads resinous or adamantine on Eulytine and vitreous to adamantine on Scheelite.
How to tell apart: Eulytine is noticeably harder (Mohs 4.5 vs. 2-2.5); streak differs, so Eulytine leaves white or yellowish gray, Bismuthinite leaves lead-gray; luster reads resinous or adamantine on Eulytine and metallic on Bismuthinite.
Often found alongside eulytine
Minerals reported to co-occur with eulytine. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi₄(SiO₄)₃
- Mohs hardness
- 4.5
- Density
- 6.62-6.76 g/cm³
- Streak
- White or yellowish gray
- Luster
- Resinous or adamantine
- Transparency
- Transparent to opaque
- Crystal system
- Cubic
- Crystal habit
- Tetrahedral crystals, rounded dodecahedrons, massive
- Cleavage
- Very imperfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In bismuth-rich hydrothermal veins
Where rockhounds find eulytine
Classic worldwide localities
- Schneeberg and Johanngeorgenstadt, Saxony, Germany
- Hechtsberg, near Hausach, and in the Clara Mine, near Oberwolfach, Black Forest, Germany
- Dognecea (Dognaczka), Romania
- Lanlivery, Cornwall, England
- Southwick cliffs, near Dalbeattie, Kirkcudbrightshire, Scotland
- Evans-Lou quarry, near Wakefield Lake, Quebec, Canada
Field-hunting tip
Where it forms: In bismuth-rich hydrothermal veins. If you start seeing bismuth, quartz in float, you are in the right ground. Typical habit: tetrahedral crystals, rounded dodecahedrons, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find eulytine on the map
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