24 APOSTLE GEMS. 



'!"ransparent to opaque. Lustre shining on 

 the lateral planes of the prism, pearly on 

 the terminal. Becomes feebly electric by 

 friction. Streak white. Brittle. Fracture 

 uneven. H 4-5 to 5. S.G. 2-3. 



Comp. Silica 527, lime 26"0, potash 4'4, 

 water 16-7 = 100. 



Analysis by Berzelius, from Faroe : 



Silica 52-38 



Lime 24-70 



Potash 5-37 



Fluorine . . . .1-20 

 Water 16-20 



99-85 

 BB exfoliates, intumesces, and ultimately 

 fuses to a white vesicular glass ; Avith borax 

 melts readily to a transparent globule. 

 In nitric acid it separates into flakes, and in 

 powder becomes gelatinous and translucent. 

 Localities. — Scotch. It is found in Old 

 Kilpatrick(/o. 29), in Dumbartonshire ; in 

 Fifeshire, at the Chapel Quarries, near Eaitli ; 

 at Talisker, in Invernesshire {fg. 28) ; and 

 in very transparent cr3'stals at Ratho, near 

 Edinburgh. — Irish. At Ballintoy, in An- 

 trim, it is met with of a white colour upon 

 Stilbite (Jig. 29) ; in small transparent 

 crystals, and in large white crystals like 

 Jig. 27, atPortrush, and at Agnew's Moun- 

 tain. — Foreign. Fine specimens of Apophyl- 

 lite, coating cavities in amj^gdaloid, occur 

 in Greenland, Iceland, Poonah, and Ah- 

 mednuggar, in Hindostan. It is also found 

 in Sweden and Norway, and in perfect, well- 

 defined crystals at Plombieres, in an ancient 

 crust of cement, which was formerly spread 

 over the valley where the hot springs rise. 



The name Apophyllite is derived from 

 a!ro<pvXkliu, to exfoliate, alluding to its be- 

 haviour before the blowpipe. 



Brit. Mus., Case 27. 



31. P. G. Horse-shoe Case, No. 1177. 



Apostle Gems. In the middle ages the 

 apostles were sometimes symbolised under 

 the names of various gems, as follows : 



St. Peter . . . Jasper. 



St. Andrew . . . Sapphire. 



St. James . . . Chalcedony. 



St. John . . . Emerald. 



St. Philip . . . Sardonyx. 



St. Bartholomew . . Carnelian. 



St. Matthew . . . Chrysolite. 



St. Thomas . . . Beryl. 



St. Thaddeus . . Chrysoprase. 



St. James the Less . Topaz. 



St. Simeon . . . Hyacinth. 



St Matthias . . Amethyst. 



Apyroti (from « priv., and ^t^? Jire). A 



AR^OXENE. 



name given by some of the ancients to Ru- 

 bies, because " fire hath no power of them." 

 Aquamarine, comprises the varieties of 

 Beryl which are of clear tints of sky- 

 blue or mountain-green. (See Beryl.) 



It is made into bracelets, necklaces, brooch- 

 es, and other articles of jewelry, as well as in- 

 to seals and intaglios. The larger prisms are 

 valued by the Turks for forming the handles 

 of daggers, sword-hilts, &c. It is a pleasant 

 stone for lapidaries to work, as it bears cut- 

 ting and polishing without risk. Want of 

 lustre, paleness and Aveakness of colour, being 

 the principal defects to which it is liable, a 

 good stone should have a sufficient depth in 

 proportion to its spread surface, and it 

 should be formed Avith a small table, a high 

 bizel, Avith the under-part cut into delicate 

 steps. The only stone Avith Avhich the Aqua- 

 marine is likely to be confounded is the blue 

 Topaz, from Avhich it maA^ be distinguished 

 by its inferior specific gravity and hardness, 

 and inferior lustre. 



It is found in Hindostan, Brazil, Siberia, 

 in the granite district of Nertschinsk, and 

 in theUralian and Altai Mountains, The 

 prisms are commonly striated longitudinally, 

 and they have been obtained exceeding a 

 foot in length. 



The most splendid specimen of which 

 we have any account belonged to Dom Pe- 

 dro. It approaches, both in size and shape, 

 the head of a calf, and exhibits a crystal- 

 line structure only on one side, the rest 

 being water-worn. It Aveighs 225 ozs. 

 Troy, or more than 18^ lbs. The specimen 

 is transparent and Avithout a flaw. 



The name is derived from aqua, Avater, and 

 marina, of the sea, in allusion to its limpid, 

 pale green colour, like that of sea-Avater. 



The Aquamarine is the stone knoAvn to 

 the ancients as the Beryl. 

 Brit. Mus., Case 37. 



M. P. G. Horse-shoe Case, Nos, 816a, 

 836 to 838. 



ArxEOXene. a mineral resembling Cro- 

 coisite, only darker. It occurs massive, or 

 imperfectly crystalline, with traces of a 

 columnar structure, of a deep red colour, 

 Avith a broAvnish tinge, and a pale yellowish 

 streak. H. 3. S.G. 5-79. 

 Analysis by Bergemann : 



Vanadic acid . . . 16-81 

 Arsenic acid . . . 10*52 



Oxide of lead . . . 62-55 

 Oxide of zinc . . . 18-11 

 Alumina and peroxide of iron 1-34 

 Phosphoric acid . . . trace 



99-33 



