Prof. Chapman on the Classification of Minerals. 181 



2. Bournonite Type i—Trimetric (D : D 96°-102°). 



Bournonite 3(Cu 2 Pb)S, SbS 3 ; aikinite* 3(Cu 2 , Pb)S, BiS 3 ; 

 wolchite; wolfsbergite Cu 2 S, SbS 3 ; jamcsonite 3PbS, 2SbS 3 . 



Boulangerite ; kobellite ; heteromorphite (plumosite) ; ber- 

 tliierite. 



3. Zinkenite Type :—Tritnetric (D : D about 120°). 

 Psaturose 6AgS, SbS 3 ; zinkenite PbS, SbS 3 ; geocronite 



(schulzite) 5PbS, (Sb, As)S 3 . This type has many relations to 

 the chalkosine type in the family of the Glances. 



4. Panabase Type: — Monometric. 



Dufrenoysite 2PbS, AsS 3 ; steinmannite xPbS, SbS 3 ; pana- 

 base (fahlerz) 4(Pb, Fe, Zn, Cu 2 , Ag,Hg)S + (Sb,As) S 3 ; tennan- 

 tite 4RS, AsS 3 . 



5. Freislebenite Type: — Monoclinic (Miller). 

 Plagionite 4PbS, 3SbS 3 ; freislebenite x(Pb, Ag)S, xSbS 3 . 



6. Polybasite Type: — Hexagonal. 



Polybasite 9(Ag, Cu 2 )S, (Sb,As)S 3 ? or 2Cu 2 S + 6AgS, (Sb, 

 As)S 3 ? 



IX. Ruby Blendes. 



1. Argyrythrose Type: — Hexagonal. 



Argyrythrose 3AgS, SbS 3 ; proustite 3AgS, AsS 3 ; xantho- 

 cone ; cinnabar HgS. 



2. Miargyrite Type: — Monoclinic. 

 Fire-blende ; miargyrite AgS, SbS 3 . 



X. Sulphoids. 



1. Sulphur Type: — Trimetric. 

 Native sulphur ; selen sulphur ; orpiment AsS 3 . 



2. Realgar Type : — Monoclinic. 

 (Monoclinic sulphur) ; realgar AsS 2 . 



* Aikinite, Chapman 1843. Subsequently named aciculite by Mr. Nicol, 

 and patrinite by Haidinger. Where the name of any distinguished culti- 

 vator of the science has been substituted for a prior name having reference 

 merely to the locality or general properties of the mineral, courtesy may 

 recognise the substitution ; but in all other cases, the original name — unless 

 manifestly inappropriate — should undoubtedly be retained. The nomen- 

 clature of mineralogy has much need of a work of purification like that 

 lately rendered to a large portion of palseontological science by M. Alcide 

 d'Orbigny. (Prodrome de Paleontologie stratigraphique universelle des 

 Animaux Mollusques et Rayonne's.) 



