Selenojalpaite is a rare silver-copper selenide mineral typically found as microscopic grains within hydrothermal deposits. It is chemically related to jalpaite but characterized by the substitution of sulfur with selenium, often identified through advanced analytical methods like SEM-EDS.
Is this selenojalpaite?
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 selenojalpaite with a known reference. Selenojalpaite sits at Mohs 4-4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: dark gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: anhedral grains.
Often confused with
Selenojalpaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Selenojalpaite is noticeably harder (Mohs 4-4.5 vs. 2-2.5).
How to tell apart: Selenojalpaite is noticeably harder (Mohs 4-4.5 vs. 2.5); streak differs, so Selenojalpaite leaves black, Aguilarite leaves grayish black.
Often found alongside selenojalpaite
Minerals reported to co-occur with selenojalpaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₃CuSe₂
- Mohs hardness
- 4-4.5
- Density
- 7.65 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Anhedral grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a mineralized hydrothermal calcite vein
Where rockhounds find selenojalpaite
Classic worldwide localities
- Skrikerum Cu-Ag-Tl selenide deposit, near Valdermarsvik, Småland, southeastern Sweden
Field-hunting tip
Where it forms: In a mineralized hydrothermal calcite vein. If you start seeing eucairite, altaite, berzelianite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify selenojalpaite?+
Where is selenojalpaite found?+
Is selenojalpaite safe to handle?+
What rocks look like selenojalpaite?+
What minerals are found with selenojalpaite?+
What kind of rock does selenojalpaite form in?+
What is selenojalpaite used for?+
Find selenojalpaite on the map
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