540 SYSTEIMATIC DESCRIPTION OF PRECIOUS STONES 



represented in Plate XX., Fig. 9. The external weathered layer is easily detachable from 

 the nucleus of fresh, unaltered material, which is often pitted with close-set, shallow, 

 conical depressions. These effects of weathering are only to be seen in specimens which 

 have lain in drv earth, those ^vhich have been embedded in perfectly dry sand being often 

 changed and altered throughout their whole mass, and the surface deeply honeycombed. 

 Material, on the other hand, which has lain in water or in moist earth, thus being ]:)reserved 

 from conta:ct with air, is often scarcely altered at all and does not show even the surface 

 sculpturing described above. 



Beside air-bubbles, the importance of which has been explained already, other 

 enclosures of A-arious kinds are found in amber, some of which are of special significance. 

 Drops of water occur not infrequently, but enclosures of solid matter, either organic or 

 inorganic, are more frequent. 



The inorganic substance most commonly enclosed in amber is iron-pyrites, which, in 

 the form of quite thin lamellae, fills up cracks and crevices in many specimens, especially of 

 shelly amber. It is also frequently enclosed in frothy amber as already stated. The 

 presence of iron-pyrites in a specimen of amber naturally interferes with the working of it, 

 and such material is of little value to the turner. 



The enclosures of organic material, partly of vegetable and partly of animal origin are 

 of great importance. The vegetable enclosures consist mostly of finely divided particles of 

 carbonised wood, which are black in colour and are present in many specimens in greater or 

 less abundance. The amber retains its usual yellow colour, and does not appear black in 

 consequence of these black enclosures. Black amber does not actually exist, what is known 

 as such being in reality quite another substance, namely, jet, which will be considered later 

 on. The black resins which sometimes occur in company with amber are quite distinct 

 from this and, further, are not suitable for ornamental purposes. The particles of 

 carbonised wood now found enclosed in amber are the remains of the pine-trees from which 

 the amber-resin was exuded, the so-called amber-pine {Pinitei- mccinifer of Goppert). 

 Larger fragments of wood, needles, and other parts of the tree, are also found as enclosures, 

 but more rarely. Recognisable remains of other plants also occur though still less 

 commonly, these often consist of flowers and leaves, the structure and form of which are 

 perfectly preserved by the amber in which they are embedded. 



This is also the case with animal remains, which are found in amber in great ninnber 

 and variety. These include insects of various kinds, such as ants, moths, and especially 

 flies ; also spiders, and as great rarities snails and other small animals. Inclusions are 

 confined almost entirely to the clear shelly amber and are scarcely ever found in turbid 

 massive amber. The animal and plant remains found embedded in amber belong to extinct 

 species, but these do not differ widely from present-day organisms. They lived and 

 flourished at the time known to geologists as the Tertiary period, and were imprisoned in 

 the resin exuded from the pine-trees living at the same time. So perfectly has their form 

 and structure been retained, that these fossil plants and animals are almost as suitable for 

 biological investigation as are living forms, often throwing light on the character of the 

 fauna and flora of the period. A piece of amber containing some organism is often cut for 

 ornamental purposes in such a way as to bring the enclosure into prominence. 



WiKxiXG OF AiMBEE.— The first amber to be collected would naturally be that which 

 had been washed up on to the beach from amber-bearing strata beneath the sea. A certain 

 amount is still obtained in this way, and is known as sea-amber or as sea-stone. It is 

 distinguished from ordinary amber by the absence of a crust of weathered material. This 

 was, no doubt, present while the substance remained in its original situation, but bv the 



