THE TECHNOLOGIST. [May 1, 1864. 



444 ON GRANITE AND ITS USES. 



silica. Of all the gems it is probably tbe least known, and the least 

 prized. It is a brown stone, of no remarkable beauty, resembling a red 

 brown garnet, which is often sold as a jacinth or hyacinth. The rarest 

 of the gems is thus the least prized of them all. 



There are other precious stones besides those which I have named ; 

 but they all consist of common things. The garnet, for example, the 

 spinelle-ruby, and lapis-lazuli or ultramarine, are compounds of the 

 ever re-appearing silica, alumina, magnesia, and iron oxide ; the splendid 

 colour of ultramarine (which we are able to imitate artificially), depend- 

 ing, in addition to these materials, on the presence of sulphur and 

 soda. 



The turquoise is clay-earth united with bone-earth (phosphate of 

 lime), coloured by oxide of copper. Many turquoises are the fragments 

 of fossil bones stained with copper. Malachite is a very common copper 

 ore. Satin spar and Derbyshire spar, besides other prized spars, consist 

 chiefly of lime. Jet is coal, and amber is petrified rosin. In short, with 

 the exception of the dull brown jacinth and the emerald, the great 

 majority of precious stones are only coloured sand, flint, clay-earth, or 

 clay, whilst the diamond is charcoal, and the pearl chalk. 



If any of my readers hear this for the first time, I can well imagine 

 them saying, " for us hitherto a diamond was a diamond, and a pearl a 

 pearl ; the sapphire the embodied azure of the shy ; and the emerald, 

 the green which the earth loves in spring. But now, much apparently 

 to your contentment, they are turned into soot and chalk, and clay, and 

 iron rust !" 



Now, I sympathise greatly with the feeling which leads to this pro- 

 test. I have pleaded that children should not too early be despoiled of 

 their romantic belief;?. And there are grown-up children of the best 

 sort, who keep the hearts of children, in manly or womanly breasts, even 

 to extreme old age, and who, I should be glad, could believe all their 

 days, that diamonds were crystallised May-dew, and pearls the tears of 

 mermaids, and sapphires chips from the vaxdt of heaven, and emeralds 

 leaves of the trees that grew in Eden. But to most of us, as even to 

 a Wordsworth, the time irrevocably comes, when the fairy gleams of 

 childhood fade into the light of common day ; and we are all the 

 descendants of her who ate of the fruit of the tree of knowledge of good 

 and of evil, and must taste, like her, the bitter as well as the sweet ; but 

 the bitter here is a Avholesome one. Why shordd we admire a diamond 

 the less because a chemist can roast it into a cinder or burn it into 

 choke-damp ? Why should a pearl be pronounced unbeautiful because 

 any one can rival the wanton Cleopatra, who changed one into a hateful 

 draught by dissolving it in vinegar ? 



There is something unconsciously atheistic, materialistic, and bar- 

 baric in the notion that the rarity of its material is the chief element in 

 the beauty of a beautiful object. All that the marble contributes to 

 the beauty of the Apollo Belvidere, or the Medicean Venus, or 



