工业上将石墨矿石分为晶质(鳞片状)石墨矿石和稳晶质(土状)石墨矿石两大类。晶质石墨矿石又可分为鳞片状和致密状两种。
中国石墨矿石以鳞片状晶质类型为主，其次为隐晶质类型，致密状晶质石墨只见于新疆托克布拉等个别矿床中，工业价值不大。
鳞片状石墨矿石结晶较好，晶体粒径大于1μm，一般为0.05～1.5mm，大的可达5～10mm，多呈集合体。矿石品位较低，一般为3～13.5%。伴生的矿物有云母、长石、石英、透闪石、透辉石、石榴石和少量硫铁矿、方解石等，有时还伴有金红石，钒云母等有用组分。鳞片石墨矿石按其所赋存岩石的岩性不同，分片麻岩型、片岩型、透辉岩型、变粒岩型、混合岩型、大理岩型及花岗岩型等七种，前六种矿石类型产于区域变质成因矿床中，后一种矿石类型则产于岩浆热液成因矿床中。
稳晶质石墨矿石一般呈微晶集合体，晶体粒径小于1μm，只有在电子显微镜下才能观察到其晶形。矿石呈灰黑色、钢灰色，一般光泽暗淡，具有致密块状、土状及层状、页片状构造。隐晶石墨的工艺性能不如鳞片状石墨，工业应用范围也较小，矿石品位一般都较高，但矿石可选性差。矿物成分以石墨为主，伴生有红柱石、水云母、绢云母及少量黄铁矿、电气石、褐铁矿、方解石等。品位一般为60～80%、灰分为15～22%、挥发分为1～2%、水分为2～7%。
The industry is divided into crystalline graphite ore (flake graphite ore) and stable crystalline (earthy) graphite ore in two categories. Crystalline graphite ore can be divided into two kinds of flake and dense.
Graphite ore in China mainly to flake crystalline type, secondly is cryptocrystalline type, dense like crystalline graphite is only seen in Xinjiang Tuoke Brad individual deposit, industrial value is not great.
Flake graphite ore crystal is good, the crystal size is more than 1 m, the average size is 0.05 ~ 1.5mm, the size of a large amount of up to 5 ~ 10mm, more than a collection. Ore grade is low, generally 3 ~ 13.5%. Associated minerals mica, feldspar, quartz, through amphibole and pyroxene, garnet and a small amount of pyrite and calcite etc., sometimes accompanied by rutile vanadium mica and other useful group. Flake graphite ore according to the occurrence of rock lithology, gneiss, schist, through eclogite, granulite type, mixed type of rock, marble and granite type seven, six kinds of ore type produced in regional metamorphic genesis. After a ore type is produced also hydrothermal deposit.
Stable amorphous graphite ore generally showed a microcrystalline aggregates, crystal grain size is less than 1 m, only under the electron microscope can be observed their crystalline form. The ore was black, steel gray, general luster dim, with dense massive, earthy and layered, lamellar structure. The process properties of amorphous graphite are not as good as that of flake graphite, and the industrial application range is small, and the ore grade is generally higher, but the ore is not available. Mineral composition in graphite mainly associated with andalusite, hydromica, sericite and a small amount of pyrite, tourmaline, limonite, calcite. The grade is generally 60 ~ 80%, ash content is 15 ~ 22%, the volatile is 1 ~ 2%, the moisture content is 2 ~ 7%.