Vapnikite is a rare calcium uranium oxide that forms yellow-brown irregular masses. Associated minerals include larnite, brownmillerite and vorlanite. It was first described from Jabel Harmun and Nabi Musa, Judean desert, West Bank, Palestinian Autonomy, Israel.
Is this vapnikite?
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 vapnikite with a known reference. Vapnikite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish white.
- 3Read the lusterHold the specimen under a strong light. Luster: strongly vitreous.
- 4Match the color rangeCompare against the expected color range: yellow-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: irregular masses.
Often confused with
Vapnikite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Vapnikite is noticeably harder (Mohs 5 vs. 2-2.5); streak differs, so Vapnikite leaves yellowish white, Ettringite leaves white; luster reads strongly vitreous on Vapnikite and vitreous on Ettringite.
How to tell apart: Vapnikite is noticeably harder (Mohs 5 vs. 3.5); streak differs, so Vapnikite leaves yellowish white, Thaumasite leaves white; luster reads strongly vitreous on Vapnikite and vitreous to dull, greasy, silky on Thaumasite.
Often found alongside vapnikite
Minerals reported to co-occur with vapnikite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂CaUO₆
- Mohs hardness
- 5
- Density
- 5.322 g/cm³
- Colors
- Streak
- Yellowish white
- Luster
- Strongly vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Irregular masses
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the Hatrurim Formation (“Mottled Zone”)
Where rockhounds find vapnikite
Classic worldwide localities
- Jabel Harmun and Nabi Musa, Judean desert, West Bank, Palestinian Autonomy, and from the Hatrurim Basin, Negev Desert, Israel
Field-hunting tip
Where it forms: In the Hatrurim Formation (“Mottled Zone”). If you start seeing larnite, brownmillerite, ye’elimite in float, you are in the right ground. Typical habit: irregular masses. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify vapnikite?+
Where is vapnikite found?+
Is vapnikite safe to handle?+
What rocks look like vapnikite?+
What minerals are found with vapnikite?+
What kind of rock does vapnikite form in?+
What is vapnikite used for?+
Find vapnikite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
