Natroboltwoodite is a rare secondary uranium silicate mineral that forms as a result of the alteration of uraninite. It typically appears as fine, fibrous yellow acicular crusts or radiating aggregates in oxidized uranium deposits. Due to its radioactive and toxic nature, it is strictly a specimen for experienced mineral collectors who employ proper containment and safety protocols.
Is this natroboltwoodite?
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 natroboltwoodite with a known reference. Natroboltwoodite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Natroboltwoodite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Natroboltwoodite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, acicular, radiating clusters.
Often confused with
Natroboltwoodite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Natroboltwoodite leaves white, Boltwoodite leaves yellow; luster reads earthy on Natroboltwoodite and pearly on Boltwoodite.
How to tell apart: Streak differs — Natroboltwoodite leaves white, Kasolite leaves yellow; luster reads earthy on Natroboltwoodite and greasy on Kasolite.
How to tell apart: Streak differs — Natroboltwoodite leaves white, Uranophane leaves pale yellow; luster reads earthy on Natroboltwoodite and vitreous on Uranophane.
Often found alongside natroboltwoodite
Minerals reported to co-occur with natroboltwoodite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(UO₂)(SiO₃OH)·1.5H₂O
- Mohs hardness
- 3-4
- Density
- 3.84 g/cm³
- Colors
- Streak
- White
- Luster
- Earthy
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Acicular, Radiating Clusters
- Cleavage
- Perfect
- Fluorescence
- Bright Green Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Uranium-bearing Hydrothermal Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find natroboltwoodite
Classic worldwide localities
- Rossing mine, Namibia
- Goanikontes, Namibia
- Grandview mine, Arizona, USA
Field-hunting tip
Look in oxidized zones of uranium-bearing hydrothermal deposits country — that is the host setting where natroboltwoodite typically forms. If you start seeing uraninite, gummite, quartz in float, you are in the right ground. Field specimens usually show a fibrous, acicular, radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natroboltwoodite?+
Where is natroboltwoodite found?+
How much is natroboltwoodite worth?+
Is natroboltwoodite safe to handle?+
What rocks look like natroboltwoodite?+
What minerals are found with natroboltwoodite?+
What kind of rock does natroboltwoodite form in?+
What is natroboltwoodite used for?+
Find natroboltwoodite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
