Copper · MyMineralBox

Crystal Structure

FCC packing — Cu.

Elemental Composition (by mass)

Element	Mass %	Visual
Cu Copper	100.00%

Computed from simplified end-member formula. Solid-solution series, water content, and trace substitutions cause real-world variation.

IMA Abbreviation (Whitney-Evans 2010)

→ Copper

Symbol = element

Standard symbol from American Mineralogist (Whitney & Evans, 2010). Used in thin-section labeling, phase diagrams, and IMA-style species records.

⏳ Long-term Aging & Care Timeline

oxidation patinayears

Trigger: air + humidity

Intervention: Copper-red surface becomes green/brown. Some collectors prefer natural patina; others use micro-crystalline wax to preserve.

Pronunciation

/ˈkɒpər/

↔ KOP-er

Latin cuprum

Tenacity

Behavior:

malleable + ductile

Under stress:

Bends and flattens

Native copper can be hammered into shapes; coins.

Luster

metallic

Bright copper-red metallic; tarnishes to green-brown.

Color Cause (Chromophore)

Chromophore:

d-electron transitions

Mechanism:

band transitions in Cu

Color produced:

orange-red

Same general mechanism as gold; different absorption energy.

Diaphaneity (Transparency)

opaque

Native metal.

Magnetism

Category:

diamagnetic

Test result:

Slight repulsion

Native Cu.

Test with rare-earth magnet (N42 or N52 neodymium). Suspend specimen on thread for sensitive paramagnetic detection. Diamagnetic minerals are weakly repelled (visible only with strong magnets like bismuth).

Specific Gravity

8.94

g/cm³

very heavy

Native copper.

For comparison: water = 1.00, glass ≈ 2.5, quartz = 2.65, corundum ≈ 4.00, galena ≈ 7.50, gold ≈ 19.3.

Streak Test

copper red

Native copper — bright metallic streak.

Streak = color of the powdered mineral. Drag specimen across unglazed white porcelain plate (Mohs 6.5). For minerals harder than the plate, crush a small flake into powder and observe color.

Mohs 2.5–3

Vickers (~) 170 HV

Knoop (~) 185 HK

Geological setting

VolcanicHydrothermal

Mohs Hardness 2.5–3

1
Talc 2
Gypsum 3
Calcite 4
Fluorite 5
Apatite 6
Orthoclase 7
Quartz 8
Topaz 9
Corundum 10
Diamond

Copper (Native) sits at 2.5–3 on the Mohs scale — can be scratched by a steel knife.

Colors:

Streak
Copper-red

Crystal system
Isometric (Cubic)

Discovery Known since antiquity

Native ElementsNative Elements

TL;DR · 1 min read

Native copper (Cu) is metallic copper in pure crystalline form. The Keweenaw Peninsula (Michigan) supplied the world's largest historical native-copper bonanza, including the famous "Ontonagon Boulder" weighing 1,680 kg.

Native copper (Cu) is metallic copper in pure crystalline form. The Keweenaw Peninsula (Michigan) supplied the world’s largest historical native-copper bonanza, including the famous “Ontonagon Boulder” weighing 1,680 kg. Native copper forms in basaltic lava flows, oxidized cap zones of copper deposits, and hydrothermal veins.