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Bandylite is a rare copper borate mineral found almost exclusively in oxidized copper deposits in Chile. It typically forms delicate, tabular sky-blue crystals that are prized by mineral collectors for their vibrant color and scarcity.

Hardness
2.5
Mohs
Luster
Vitreous, pearly on cleavage surfaces; dull when altered
Streak
Pale blue
Transparency
Transparent

Is this bandylite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch bandylite with a known reference. Bandylite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: pale blue.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous, pearly on cleavage surfaces; dull when altered.
  • 4
    Match the color range
    Compare against the expected color range: dark blue.
  • 5
    Look at form & habit
    Crystal system: tetragonal. Typical habit: tabular crystals.

Often confused with

Bandylite vs. its common look-alikes, and how to tell them apart in the field.

Turquoise mineral
mineral
Turquoise
Mohs 5-6

How to tell apart: Turquoise is the harder of the two (Mohs 5-6 vs. 2.5); streak differs, so Bandylite leaves pale blue, Turquoise leaves white to pale greenish blue.

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Often found alongside bandylite

Minerals reported to co-occur with bandylite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
CuB(OH)₄Cl
Mohs hardness
2.5
Density
2.810 g/cm³
Colors
Dark blue
Streak
Pale blue
Luster
Vitreous, pearly on cleavage surfaces; dull when altered
Transparency
Transparent
Crystal system
Tetragonal
Crystal habit
Tabular crystals
Cleavage
{001}, perfect
Rarity
Rare
Uses
Collector
Host rock
Of secondary origin, in a leached zone above massive iron sulfates (Quetena, Chile)

Where rockhounds find bandylite

Classic worldwide localities

  • Quetena, west of Calama, and near Taltal, Antofagasta, Chile

Field-hunting tip

Where it forms: Of secondary origin, in a leached zone above massive iron sulfates (Quetena, Chile). If you start seeing atacamite, eriochalcite, starkeyite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bandylite?+
Mohs hardness is 2.5. Luster: vitreous, pearly on cleavage surfaces; dull when altered. The streak is pale blue. Common colors include dark blue.
Where is bandylite found?+
Notable localities include Quetena, west of Calama, and near Taltal, Antofagasta, Chile.
Is bandylite safe to handle?+
Bandylite contains copper. Contains copper, handle with care and wash hands after contact to prevent ingestion or skin irritation.
What rocks look like bandylite?+
Bandylite is most often confused with Turquoise. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with bandylite?+
Bandylite commonly co-occurs with Atacamite, Eriochalcite, Starkeyite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does bandylite form in?+
Where it forms: Of secondary origin, in a leached zone above massive iron sulfates (Quetena, Chile). Working float back to the host body is the standard way to chase a fresh occurrence.
What is bandylite used for?+
Bandylite is used in collector.

Find bandylite on the map

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