Shun­gite is an ancient and unique nat­ur­al min­er­al in its prop­er­ties. One of its key char­ac­ter­is­tics is the pres­ence of a rare form of car­bon molecules—fullerenes. The min­er­al is con­sid­ered both a meta­mor­phic rock and a min­er­aloid. It has sorp­tion, cat­alyt­ic and bac­te­ri­ci­dal prop­er­ties.

In 1877, Olek­san­dr Inozemt­sev iden­ti­fied the rock as a new extreme mem­ber in the series of nat­ur­al non-crys­talline car­bon, which is not hard coal, and gave the name — shun­gite, after the name of the Zaonezh vil­lage of Shun­ga, where the rock was first dis­cov­ered and oper­at­ed.

Shun­gite is includ­ed in the list of min­er­als of nation­al impor­tance, approved by Res­o­lu­tion of the Cab­i­net of Min­is­ters of Ukraine No. 827 of Decem­ber 12, 1994, as elec­tri­cal and radio-tech­ni­cal raw mate­ri­als.

Properties of shungite

Pre­vi­ous­ly, the sig­nif­i­cance and prop­er­ties of shun­gite were under­es­ti­mat­ed, so it was main­ly used as a sub­sti­tute for coke in blast fur­nace pro­duc­tion, as well as a filler for rub­ber and sim­i­lar spheres. Shun­gite rocks are char­ac­ter­ized by high elec­tri­cal con­duc­tiv­i­ty and strong physi­co­me­chan­i­cal sta­bil­i­ty, and con­sist of var­i­ous com­po­nents (car­bon, quartz, com­plex sil­i­cates). Lat­er, sci­en­tists iden­ti­fied sev­er­al valu­able prop­er­ties, includ­ing:

• bac­te­ri­ci­dal
• sorp­tion
• restora­tive
• cat­alyt­ic
• the abil­i­ty to shield radio and elec­tro­mag­net­ic radi­a­tion

Classification

In geo­log­i­cal clas­si­fi­ca­tion, shun­gites are divid­ed into five cat­e­gories, which dif­fer in age and car­bon con­cen­tra­tion:

• Cat­e­go­ry I (youngest): noble shun­gite, vit­re­ous, black in colour with a char­ac­ter­is­tic metal­lic lus­ter, con­tain­ing 98–100 % car­bon, of which approx­i­mate­ly 0.01 % is rep­re­sent­ed by fullerenes.
• Cat­e­go­ry II: black shun­gite with a car­bon con­tent of 35 to 80 %.
• Cat­e­go­ry III: gray shun­gite con­tain­ing 20–35% car­bon.
• Cat­e­go­ry IV (one of the old­est): char­ac­ter­ized by a car­bon con­tent of 10 to 20 %.
• Cat­e­go­ry V (old­est): has the low­est con­cen­tra­tion — from 1 to 10 % car­bon.

Shun­gite rocks of cat­e­gories IV and V are usu­al­ly called shun­gite coal.

Shun­gite-con­tain­ing (less than 10% C) and shun­gite (more than 20% C) rocks are cur­rent­ly used, the main com­po­nents of which are shun­gite car­bon (20–40%), quartz (40–50%) and alu­mi­nosil­i­cates (15–25%). The first group is used for the pro­duc­tion of shungisites.

Formation of shungite

Shun­gite forms from organ­ic sapro­pel­ic sed­i­ments, which over time are cov­ered by new lay­ers, com­pact­ed, dehy­drat­ed, and sank to a con­sid­er­able depth. Under the influ­ence of pres­sure and ele­vat­ed tem­per­a­ture, slow meta­mor­phic process­es occur, dur­ing which amor­phous car­bon is dis­persed with­in the min­er­al matrix in the form of spe­cif­ic shun­gite glob­ules. Thus, shun­gites are formed as a result of nat­ur­al cok­ing process­es, which are accom­pa­nied by the tran­si­tion of organ­ic car­bon into an amor­phous vari­ety under the influ­ence of green shale meta­mor­phism of sed­i­men­ta­ry and vol­canogenic-sed­i­men­ta­ry rocks.

Pure shun­gite is quite rare in nature, occur­ring main­ly as thin veins up to 30 cm wide. More com­mon­ly, it is present as an admix­ture in shun­gite shales and dolomites.

Deposits

There are two main types of shun­gite deposits:

• Non-strat­i­fied type, rep­re­sent­ed by small veins and nests of shun­gite.
• Strat­i­fied type, rep­re­sent­ed by aged lay­ers of shun­gite-bear­ing rocks in sed­i­men­ta­ry and sed­i­men­ta­ry-vol­canogenic for­ma­tions.

Indus­tri­al deposits of shun­gite and shun­gite-con­tain­ing rocks are con­cen­trat­ed main­ly on the ter­ri­to­ry of Kare­lia (Ginoz­er deposit) and Kaza­khstan. In Ukraine, deposits and man­i­fes­ta­tions of shun­gite and shun­gite-con­tain­ing rocks are unknown.

Uses of shungite

One of the main areas of use of shun­gite rocks is fer­rous and non-fer­rous met­al­lur­gy. In high-tem­per­a­ture met­al­lur­gi­cal process­es (liq­uid slag removal, elec­trother­mal pro­duc­tion of fer­roal­loys, pro­cess­ing of nick­el-con­tain­ing raw mate­ri­als, syn­thet­ic cast iron, phos­pho­rus, non-fer­rous met­als), shun­gite rocks can serve as a com­plex raw mate­r­i­al that simul­ta­ne­ous­ly replaces coke and quartzite. In such cas­es, vari­eties con­tain­ing 25–40% shun­gite car­bon, 40–50% quartz, and 15–25% alu­mi­nosil­i­cates are used.

Shun­gite is also used as a key com­po­nent in the mod­i­fi­ca­tion of inter­nal com­bus­tion engines, gear­box­es, auto­mo­tive reduc­ers, and var­i­ous mechan­i­cal sys­tems, includ­ing indus­tri­al appli­ca­tions.

Shun­gite rocks are char­ac­ter­ized by high adsorp­tion capac­i­ty, which makes it pos­si­ble to use them as an adsor­bent in the treat­ment of waste­water and gas emis­sions. High cat­alyt­ic activ­i­ty, sta­bil­i­ty and elec­tri­cal con­duc­tiv­i­ty of shun­gites are used in elec­tro­chem­i­cal process­es and catal­y­sis. Recent­ly, shun­gite-con­tain­ing chlo­rite shale with a shun­gite car­bon con­tent of 1–3% has been used to obtain intu­mes­cent arti­fi­cial crushed stone (shungisite).