HAT 



[212] 



H E L 



HA'TCHETINE. A variety of bitumen, 

 known also as mineral adipocere, 

 found in the iron ore of Merthyr 

 Tydvil in Glamorganshire. It is 

 insoluble in water, but soluble in 

 alcohol and ether. It fuses at 

 160. It is of the hardness of soft 

 tallow. 



HATTSMA'JSTNITE. } Pyramidal manga- 



HAUSSMA'NNITE. ) nese-ore. The 

 Manganese oxyde* hydrate* of Haiiy. 

 It occurs in porphyry, in veins, in 

 America and Germany. It is of a 

 brownish -black colour. It consists, 

 according to Turner, of 98-10 of 

 red oxide of maganese, silica 0-34, 

 oxygen 0'21, baryta O'll, water 

 0-43. 



HATIYNE. Dodecahedral Zeolite, or 

 Lapis Lazuli. 



HEA'VY SPAE. Sulphate of barytes, 

 baroselenite, or prismatic heavy 

 spar. The Baryte sulphatee of 

 Haiiy ; the Schwer spath of Wer- 

 ner; and Prismatischer halbaryte 

 of Mohs. There are several varie- 

 ties of this genus, namely, the 

 compact heavy spar, having a 

 splintery and uneven fracture ; the 

 fibrous heavy spar ; the straight 

 and curved lamellar heavy spar; 

 the radiated heavy spar ; the fetid 

 heavy spar, giving out, on friction 

 a hepatic odour, whence it is also 

 called hepatite ; the earthy heavy 

 spar ; the prismatic heavy spar. 



Heavy spar consists of baryta 66 

 parts and sulphuric acid 34 parts. 

 It frequently contains a trace of 

 silex, alumine, oxide of iron, and 

 sometimes of sulphate of strontian. 

 It occurs in veins, both massive 

 and crystallized, in many parts of 

 England, Ireland, Scotland, and 

 Germany, being found in primary, 

 transition, and secondary rocks. It 

 is of different colours. It strongly 

 decrepitates when heated, and fuses 

 into a white enamel, which in the 

 course of some hours falls into pow- 

 der. One of the most striking 

 characters of this mineral is its 



great specific gravity, which varies 

 from 4-29 to 4-50. It is from this 

 circumstance it has obtained its 

 name. It is harder than crystal- 

 lized carbonate of lime, but may be 

 scratched by fluate of lime. Heavy 

 spar may be confounded with sul- 

 phate of strontian, but its specific 

 gravity is greater. After fusion, 

 the enamel produced from heavy 

 spar, if applied to the tongue, pro- 

 duces a taste similar to that of 

 rotten eggs, this does not occur in 

 the enamel of sulphate of strontian. 



HEDENBER'GITE. An earthy mineral 

 so named after Hedenberg, who 

 first analysed it ; it is a variety of 

 hornblende, and is found near 

 Tunaberg, in Sweden. 



HE'LICAL. (Mice, Fr. eV Gr.) 

 Spiral ; winding. 



HE'LIOLITES. A genus of fossils 

 found in the Silurian rocks. 



HE'LIANTHOIDA. Just as we may see 

 the Helianthoida and Ascidioida of 

 our seas fixed to their boulders and 

 rocky skerries. Hugh Miller. 



HE'LIOTBOPE. (heliotrope,^? eliotropia, 

 It. heliotropium, Lat. 

 Gr. from ^Xtos and 



1 . A plant, the turnsole. 



2. Heliotrop of Werner. Quartz- 

 agathe vert obscur et ponctue of 

 Haiiy. Called also Blood-stone. A 

 variety of rhombohedral quartz, of 

 a deep green colour, with dissemi- 

 nated spots of yellow and red jasper. 

 It is more or less translucent, in 

 which respect it differs from jasper. 

 It occurs massive. By some min- 

 eralogists it is supposed to be cal- 

 cedony, coloured by chlorite or 

 green earth. Fracture imperfectly 

 conchoidal. Specific gravity about 

 2 -63. It consists of silica with 

 about seven per cent, of alumina 

 and five per cent, of iron. It is 

 infusible before the blow-pipe. 

 The finest specimens are brought 

 from Siberia and Bucharia. Like 

 agate, it is employed in forming 



