elements
Graphite
C
- Also known as
- plumbagoblack lead
- Crystal system
- hexagonal
- Hardness
- 1–2 on the Mohs scale
- Lustre
- metallic
- Colour
- Steel grey to black
- Where it forms
- By metamorphism of carbon-rich sediments — graphite is dead organic matter cooked until only the carbon remains.
- Chiefly from
- Sri LankaMadagascarChinaCumbria, England
Why it is that colour
Carbon in sheets. It is opaque and grey because the delocalised electrons within each sheet absorb light across the spectrum.
Safety
Safe to handle and safe to write with. Pencil lead has contained no lead since the name was applied by mistake.
Where it comes from
China dominates world production. Graphite is a critical mineral for lithium-ion batteries, where it forms the anode, and demand has risen sharply.
Historical use
A deposit of exceptionally pure graphite at Borrowdale in Cumbria, found in the 1500s, was the origin of the pencil industry and was guarded by armed men and eventually by act of parliament. It was called plumbago, lead ore, because nobody knew what it was, and the pencil kept the name.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
Worth knowing
Graphite and diamond are the same element. Carbon atoms bonded in flat sheets that slide over one another give the softest common mineral, usable as a lubricant and as something you can write with; the same atoms bonded in a rigid three-dimensional lattice give the hardest natural substance. There is no chemical difference at all.
They are the standard example of polymorphism, and it is worth sitting with, because it undercuts a common intuition. Whatever a substance does is not a property of what it is made of. It is a property of the arrangement.
Graphene — a single graphite sheet — was isolated in 2004 by Andre Geim and Konstantin Novoselov using adhesive tape on a lump of this, and it won the 2010 Nobel Prize in Physics.
Identity checked against IMA-CNMNC master list, June 2025.