OHDEBVU. DODECAHEDRAL GARNET. S65 



II. S. 622. Hessonit. LEONH. S. 433. Kaneelstein. 

 HAUY. TabL comp. p. 62. Essonite. Traite, 2de Ed. 

 T. II. p. 541. 



The forms are said by HAUY to be prismatic, and 

 traces of cleavage parallel to a prism of 102 40'. It is 

 generally found in grains. Fracture imperfect and small 

 conchoidal, uneven. Surface uneven and gibbous. Lustre 

 vitreous, inclining to resinous. Colour intermediate be- 

 tween hyacinth-red and orange-yellow. Streak white. 

 Transparent ... translucent. Hardness = 7*0 ... 7'5. Sp. 

 Gr. = 3-636. It also occurs massive, presenting granular 

 composition. 



It will depend upon the investigations of the regular 

 forms of cinnamon-stone, whether or not it is to be consi- 

 dered as a species of its own. If these belong to the pris- 

 matic system, as is indicated by HAUY, no doubt can exist 

 in regard to the propriety of his erecting it into a particu- 

 lar species. But the close agreement of all its properties 

 with those of dodecahedral Garnet, and the tessular forms 

 inferred from the optical observations of M. BIOT and Dr 

 BREWSTER, which are not contradicted by HAUY, who 

 quotes simple refraction among the characters, render it ex- 

 tremely probable, that it is a variety of dodecahedral Garnet. 

 Cinnamon-stone consists, according to KLAPHOTH, of 



Silica 38-30. 



Alumina 21-20. 



Lime 31-25. 



Oxide of Iron 6-50. 



Itdoes not at first assume a darker colour before the blowpipe 

 but melts easily into a brownish-black globule. It occurs in 

 the sand of rivers and in primitive rocks with prismatic 

 Augite-spar in Ceylon. It is found massive at Kincardine 

 in Ross-shire. But it is difficult to quote localities, as the 

 varieties can be hardly distinguished from others of dode- 

 cahedral Garnet. It is used as a gem, which fetches a good 

 price, if large, well coloured and transparent, and goes ge- 

 nerally by the name of Hyacinth. 



