MINERALS FROM NEW CALEDONIA. 235 
apart as rock cork ; it, moreover, presents in parts a more or less 
well-developed petaloidal structure. The specific gravity is 2°55, 
meerschaum being only about 1°3 to 16. There are occasiona 
black dendritic markings within it. 
One specimen possessing a By pale green tinge gave the follow- 
results :— 
ing — 
Water lost at 100 a S ae oe ee 
», combin “i s- 
Silica 51°81 
2 soluble . 
lumina ... so Se ; 
Tron sesquioxide ... Rp of 7 
Nickel oxide (NiO) cv sei me 2°32 
Magnesia ... = oe <a Poy A ber * 37 
Two other nog devoid of any green einige te the fol- 
lowing results 
Analysis. an 
Water lost at 100° C. . 11°77 13°30 at 105° C} 
ev — at red heat... 9°70 8°58 by diff. 
Sili 53°80 53°80 
Biaiiek ie sas ... absent : 
on ... absent trace 
Nickel protoxide . 58 
Magnesia - 24°82 _ 22°99 
100°33 Leibius 100°00 
The above composition furnishes the fo formula :—2 MgO, 
3 Si0,, 5H,0, or 2 MgO,38i0,,H,0, if the water driven off at 
C. be disre 
100° 
The brownish or plum-coloured serpentine with which ~ 
houmeaite is often associated usually contains alumina, iron, ; 
ence (in cases where analyses show the presence of any con- 
siderable quantity of these) it may be, I think, assumed that the 
mineral has not been ca, separated from its gangue, but 
that both have been take tog 
‘he following a: yses eX some of the dark green brecciated 
ores, from which the e had not been wholly re- 
Sai will serve to show 
ater lost at 105° C. sce BGS 8-016 8°65 
Combined, by difference ...  9°034 67550 8-95 
ee 38°108 36°79 
>» Soluble ... aie oe arf on “70 
a SON TIE 2584 5-36 
somniaxide gay ie “157 1°137 
Nickel —: he Ge, ee 31-853 24°72 
Lime a absent trace 
19°083 11°752 14°97 
100-000 100-000 100°14 
