The principal markets for amber are Constantinople, Vienna, Moscow, Paris, London, and New York; the German towns chiefly engaged in the trade in raw and worked amber are Dantzig, Ktinigsberg, Stolpen, Breslau, and Lilbeek. The commercial varieties of the resin are divided into seven classes, based upon physical characteristics :—(1) " Shining" (luisant), pale-yellow or greenish ; (2) " bastard " (lmitard), opaque, citron-yellow to dark-yellow ; (3) " bone-coloured " (couleue d'os), dull-white, very rich in suecinic acid ; (4) " agate-eoloured " (couleur d'agate); (5) " impure," containing organic remains ; (6) " cloudy " (nuageux), unequally coloured, mainly clear-yellow ; (7) " transparent," of various colours. The values vary widely with the size, form, and colour of the pieces, and the kind most esteemed in one mai ket neglected in another. An approximato seale of prices is as fellows :—For mouth-pieces : 1 lb. in 9 pieces, 66s.; 1 lb. in 18 pieces, 15s. ; 1 lb. in 40 pieces, 30s.; 1 lb. in GO pieces, 19s. 6d.; 1 lb. in 100 pieces, 12s.; 1 lb. iu 200 pieces, 9s.; for heads: 1 lb. in 30 pieces, 30s. ; 1 lb. in 60 pieces, 188.; 1 lb. in 100 pieces, 12s.
Crude amber occurs in commerce in pieces of irregular size and form ; that from the mines is usually angular, with a rugose surface, while that from the sea is generally somewhat rounded by attrition, and smooth. The fracture as a rule is conchodial, and more or less lustrous. The con sistence is solid, hard, and brittle. The sp. gr. commonly ranges between 1.05 and 1.095, the average being 1.065-1.070. Amber is devoid of odour end flavour at ordinary temperatures, but it affords a strong pleasant aroma when rubbed, pulverized, or burned. It is on this account employed in the perfume called eau de luce (see Perfumes, p. 1532). The gradations of colour have already been alluded to. Blue is due to ferric phosphate ; cloudiness is caused by enclosed water in ordinary eases, but by excess of suceinic acid (often in the free state) in the bone-like specimens. The eloudiness produced by entangled water can be e,ompletely retnoved by boiling in oil. Expo sure to light darkens the colour of light-tinted amber. Amber is almost completely insoluble in water, ammonia, acetic acid, carbon bisulphide, benzol, and petroleum-spirit ; slightly soluble in alcohol, ether, turpentine, chloroform, and volatile oils ; and eempletely soluble in alkaline solu tions containing camphor, and in a mixture of alcohol and turpentine-oil heated in a elosed vessel. On boiling for 20 hours in linseed- or rape-oils, or heating for 40 hours in a sand-bath, it becomes transparent and ductile, allowing itself to be moulded into any form, and even enabling pieces to bo cemented together. Subjected to dry distillation, it affords amber-oil (see p. 1416), succinic acid, and a solid residue. The applie,ations of amber are chiefly as an article of ornamental turnery for the mouth-pieces of pipes and cigar-holders and for beads ; for the preparation of a superior varnish (see Varnish); and for the production of amber-oil and suceinie acid. As a medicinal agent it is
extinet ; and as a perfume, is chiefly used in the East. Our imports of it are en an increasing scale :—in 1853, 43 cwt.; in 1867, 60 cwt. ; in 1870, 329 cwt. It is very extensively repla,ced by a false amber composed of copal, camphor, and turpentine, and costing but a mere fraction of the price of the true article. Simple tests by which the two substances can be distinguished are :—(1) Heated ea a plate, tho false will soon melt, while the true will bear a high temperature ; (2) covered with sulphuric ether, the false is dimmed and softened, so that a penlmife will pierce it ; (3) on ignition, the true swells but does not run, while the false melts at once into drops ; (4) amber is insoluble in cajuput-oil, while copal is quite soluble ; (5) amber emits sulphuretted hydrogen when strongly heated.
Ammoniacum (F'a., Gomme-Ammoniague; GER., Ammonfakgummi). —The true ammoniacum of commerce is produced chiefly, if not exclusively, by Dorema Ammoniacum. This plant, the ushak of the Persians, occurs over a wide stretch of the barren country of W. Asia, particularly in the Persian provincea of Farsistan, Irak, and Khorasan. Bunge and Bienert place its north-western limit at Shabrud, S.-E. of Asterabad, whence it ranges eastwards to the deserts lying to the S. of the Sea of Aral and the Bir-Daria, while southwards it has not been met with beyond Baairan, a village of S. Khorasan (in 32° N. lat., and 59° E. long.). Dr. Grant found it abundantly in Syghan, near Bamian, on the N.-W. slope of the Hindu-Huah Mountains. One of the chief localities for the production of the gum-resin is the desert plain about Yezdilchast, between Ispahan and Shiraz.
The plant attaina a height of 7 ft., and almoat all portions of it, the stem, roots, leaves, and fruit,s are permeated by a milky juice, which escapes abundantly on the alightest puncture. Arti ficial tapping ia not resorted to, the operation being performed by beetles, which, in the month of May, attack the plants in multitudes, and pierce them all over. The juice exudes in drops, which rapidly harden in the sun, and either remain attached to the plant, or fall to the ground. The pro duct of this exudation, together with minor quantities which ooze out from the 3-4-year-old roots, and from the fibrous crown of the root, is collected in July-August by the peasants, and sold to dealers for transport to Ispahan or the coast. The gum-resin reaches Europe by way of the Persian Guif and Bombay. The imports into Bombay from the Gulf were 327 cwt. in 1869-70, 520 cwt. in 1870-1, 164 cwt. in 1871-2, and 1671 cwt. in 1872-3; the re-exports from Bombay to the United Kingdom were 453 cwt. in 1871-2.