as free as possible, by aid of the magnifier, from magnetite, gave 
42°69 per cent ; this, considering the difficulty of selecting abso- 
Intely pure material and the fact that the mineral, althoug 
almost entirely, is not completely, decomposed by acid, shows 
that the iron is most probably present only as protoxyd. 
The calculation of the oxygen for the mean of the two analy- 
; ses gives the ratio of Si: k as 17°91 : 17°56 or 1:1, in which the 
relation of the iron to the magnesia is very nearly as 3:2, and 
the composition of the mineral is that of an iron-magnesia- 
manganese chrysolite. In chemical i aiaeon this member 
of the chrysolite family is between hyalosiderite and fayalite, 
although it differs very materially from both, as will be seen by 
tam the analysis with these and allied varieties. 
| G. J. Brush on Hortonolite. 19 
F 
i 
Si Al Fe Mn Mg Ga K Gu 
1. Hyalosiderite, 31:63 2:21 29-71 0-48 a — 2°79 —— Or tr=—99-22, W 
2. Dalarne chrysolite, ~ 20 1°93 35°55 0. . -—- — w. Ni,Sntr.=99°51,8 
3. New chrysolite, 3°59 —— 44°37 4 eee tr. 039 —— =99-64, Mixter. 
4. Eulysyte “ 29 16 1°56 55°87 8° i 3-232°29 — —— =100-58, Erdm. 
5. Fayalite, Fayal, 28°27 3°45 63°80 tr. 0°45 — 1:29 FeS3-35—100°61,R 
1. Hyalosiderite, Walchner, Schweigger, Journ. xxxix, 65. 2. Analysis made 
i pee given by Soe sae in Ak. H. Stockholm, 184 1848, E 2. 3. This article. 
Erdmann, Min, 278, 5, Rammelsberg, Min. Chem., 
The new mineral contains more iron than hyalosiderie, with 
a correspondingly smaller amount of magnesia, while the 
site is true with fayalite. It more nearly approaches the vari- 
ety of iron-manganese chrysolite described by Erdmann as oc- 
curring near T'unaberg in Sweden, associated with garnet and 
this, however, it differs in containing 13 per cent more magne- 
sia, and about 1 per cent less iron and manganese, and no lime. 
The mineral therefore, forms a marked variety of iron-magnesia- 
manganese chrysolite. 
In view of these facts, it is proper to designate this new vari- 
ety with a special name, and I propose for it the name Hor- 
tonolite, after Mr. Horton, who first discovered the mineral, If 
found in quantity, this may prove to be a valuable iron ore, if 
smelted with more basic or calcareous ores. It is free from 
undesirable impurities, while it contains a considerable amount 
manganese. There is reason to believe that it Pice occur in 
sufficient abundance to be of economic importan 
It gives me pleasure to acknowledge my ‘ndebtodleiias to Mr. 
Horton for kindly supplying me with specimens of this mineral 
for examination; to Mr. W. G. Mixter, assistant in the Sheffield 
laboratory, for aid in the chemical investigation ; and to Mr. 
John M. Blake for his discussion of the crystallographic char- 
acters of the mineral which here follows. 
