- Vein, aka lump graphite, is coarsely crystalline, a small specialized market, and the highest-priced natural graphite. It is produced from Sri Lanka mines by hand-sorting and comprises only 1% of the market.
- Flake graphite is categorized by crystal size with large (+80 mesh), medium (-80 to +100 mesh), and fine (-100 to +300 mesh). Marketable products must grade 94-97% graphitic carbon (Cg) and are used for both traditional and new applications. Flake constitutes 49% of the market.
- Amorphous powder graphite a misnomer. It is actually crystalline but very fine grained (-300 mesh). At 80-85% Cg, the amorphous variety is used for lower-priced applications and amounts to 50% of the total natural graphite market.
In general, larger crystal sizes and higher Cg content command higher prices per tonne.
Demand has increased over the past 18 years, although not exactly year over year. The natural graphite industry is strongly correlated with world economic health, illustrated by the chart below:
Rapid growth in demand has led to significant price increases over the past three years:
Source: Industrial Minerals Inc.
Many specialized markets command premium prices but require further purification and processing. Examples include spherical graphite, necessary for Li-ion batteries, and expanded graphite, used increasingly in heat-sensitive applications.