Sampleite is a rare copper-calcium phosphate mineral known for its distinctive bright blue to greenish-blue color. It typically forms delicate, platy crystals or rosettes found within the oxidized zones of copper-rich hydrothermal deposits.
Is this sampleite?
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 sampleite with a known reference. Sampleite sits at Mohs ~4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: bluish white.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly on {010}.
- 4Match the color rangeCompare against the expected color range: bluish green, light blue.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: aggregates, lath, rosette.
Often confused with
Sampleite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Turquoise is the harder of the two (Mohs 5-6 vs. ~4); streak differs, so Sampleite leaves bluish white, Turquoise leaves white to pale greenish blue; luster reads pearly on {010} on Sampleite and vitreous in crystals; dull to waxy if massive on Turquoise.
How to tell apart: Sampleite is noticeably harder (Mohs ~4 vs. 1.5-2); streak differs, so Sampleite leaves bluish white, Vivianite leaves white, altering to dark blue, brown; luster reads pearly on {010} on Sampleite and vitreous, pearly on the cleavage, dull when earthy on Vivianite.
How to tell apart: Streak differs, so Sampleite leaves bluish white, Vauxite leaves white; luster reads pearly on {010} on Sampleite and vitreous on Vauxite.
Often found alongside sampleite
Minerals reported to co-occur with sampleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCaCu₅(PO₄)₄Cl·5H₂O
- Mohs hardness
- ~4
- Density
- 3.20 g/cm³
- Colors
- Streak
- Bluish white
- Luster
- Pearly on {010}
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Aggregates, lath, rosette
- Cleavage
- {010}, perfect; {100}, {001}, good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare mineral in the oxidized zone of copper deposits in arid climates; in caves, derived from copper sulfides in the cave walls and phosphate from bat guano
Where rockhounds find sampleite
Classic worldwide localities
- Antofagasta, from Chuquicamata, Chile
- Fortuna mine, east of Baquedano, Chile
- Mantos Blancos, Chile
- Santa Catalina mine, Sierra Gorda district, Chile
- El Guanaco mine, near Taltal, Chile
- Tsaobismund pegmatite, 60 km south of Karibib, Namibia
Field-hunting tip
Where it forms: A rare mineral in the oxidized zone of copper deposits in arid climates; in caves, derived from copper sulfides in the cave walls and phosphate from bat guano. If you start seeing atacamite, libethenite, pseudomalachite in float, you are in the right ground. Typical habit: aggregates, lath, rosette. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sampleite?+
Where is sampleite found?+
Is sampleite safe to handle?+
What rocks look like sampleite?+
What minerals are found with sampleite?+
What kind of rock does sampleite form in?+
What is sampleite used for?+
Find sampleite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
