446 



MINERALOGY. 



Oryctogno- connects the brown series with the black. Varieties 

 y- of this colour occur frequently in the mineral king- 



^~~v~~' dom, particularly among the ores of iron, and the 

 inflammable minerals. 



a. Reddish-brown is chestnut-brown mixed with a little 

 red and yellow ; or chestnut- brown with a small 

 portion of aurora-red. It passes into brownish- 

 red. Example, brown blende from the Hartz, and 

 zircon. 



b. Clove-brown is chestnut-brown, mixed with cochi- 

 neal-red, and a little black. It is the colour of the 

 clove. It passes into plum-blue and cherry-red. 

 Examples, rock-crystal, brown hematite, and axinite. 



c. Hair-lirotvn is clove-brown mixed with ash-grey. 

 Examples, Cornish tin-ore, wood opal, and brown 

 iron-ore. 



d. Broccoli-brown is chestnut-brown mixed with much 

 blue, and a small portion of green and red. It pas- 

 ses into cherry-red and plum-blue. It is a rare co- 

 lour. Example, zircon. 



e. Cheslnut-broivn. Pure brown colour. It is a rare 

 colour. Example, jasper. 



f. Yellowish-brown is chestnut-brown mixed with a 

 considerable portion of lemon-yellow. It passes into 

 ochre-yellow. It is one of the most common colours 

 in the mineral kingdom. Examples, iron-flint and 

 jasper. 



g. Pinch beck-brown is yellowish-brown with metallic 

 lustre. Rather the colour of tarnished pinchbeck. 

 Example, mica. 



h. Wood-brown is yellowish-brown mixed with much 

 pale ash-grey. It passes into yellowish-grey. 

 Mountain wood, and bituminous wood. 



i. Liver-brown is chestnut-brown mixed with olive- 

 green and ash-grey. It is the colour of boiled, not 

 fresh liver. It passes into olive green. Example, 

 common jasper. 



k. Blackish brorvn is chestnut-brown mixed with black. 

 It passes into brownish-black. Examples, mineral 

 pitch from Neufchatel, moor-coal, and bituminous 

 wood *. 



The immense variety of colours that occur in the 

 mineral kingdom, constitute an almost infinite series, 

 to characterise every individual of which is next to im- 

 possible. The colours we have already defined, are a 

 few only of the most prominent features of that great 

 and beautiful series, and serve as points of comparison, 

 and as the boundaries between which every occurring 

 colour lies. 



From the small number of colours we have defined, 

 and the great variety that occur in minerals, it is evi- 

 dent that the greater number of occurring colours will 

 not correspond exactly with those defined, but will lie 

 between them. It is this circumstance, in particular, 

 that renders it so difficult to get an acquaintance with 

 colours. To obviate this in some degree, WERNER 

 uses terms which express correctly certain prominent 

 differences which are to be observed between every 

 two colours. Thus, when one colour approaches 

 slightly to another, 'it is said to incline towards it, (es 

 nShrt sich ;) when it stands in the middle between 

 two colours, it is said to be intermediate, (es steht in 

 der mitte ;) when, on the contrary, it evidently ap- 

 proaches very near to one of the colours, it is said to 

 fall or pass into it, (es geht iiber). 



II. The Delineations or Patterns formed by the Colours. 



The distinctions included under this head depend on 

 the shape which the colour assumes. It is only to jj, 

 be observed in simple minerals. The following are p a 'uern r 

 the different kinds enumerated and described by formed by 

 WERNER. the colours. 



A. Dolled. In this variety, dots or small spots are ir- 

 regularly dispersed over a surface which has a dif- 

 ferent colour from the spots. It occurs frequently 

 in serpentine, but seldom in other minerals. 



B. Spotted. If the spots are from a quarter of an inch 

 to an inch in diameter, and the basis or ground still 

 visible, it is said to be spotted. It is either round 

 and regularly spotted, or irregularly spoiled. The 

 first occurs in clay. slate ; the second in marble. 



C. Clnuded. Here no basis is to be observed ; the 

 boundaries of the colours are not sharply marked, 

 and the spots run into each other. It occurs in 

 marble and jasper. 



D. Flamed. When the spots are long and acuminated, 

 and arranged according to their length, the flamed 

 delineation is formed. It has still a basis. It occurs 

 in striped jasper, marble, &c. 



E. Striped. Consists of long and generally parallel 

 stripes, that touch each other and fill up the whole 

 mass of the stone, so that it has no ground. It pre- 

 sents two varieties. 



a. Straight striped, as in striped jasper and varie- 

 gated clay. 



b. Ring-shaped, occurs in Egyptian jasper. 



F. Veined. Consists of a number of more or less de- 

 licate veins crossing each other in different directions, 

 so that it is sometimes net-like. We can always dis- 

 tinguish a base or ground. Examples, black marble 

 veined with calcareous spar or quartz, jasper and 

 serpentine. 



G. Dendritic. Represents a stem with branches, on a 

 ground. Examples, steatite and dendritic calcedony. 



K. Ruinifnrm. Resembles ruins of buildings. It oc- 

 curs in Florentine marble, which is from this cir- 

 cumstance called landscape marble. 



III. The Play of the Colours. 



If we look on a mineral which possesses this pro- The ply of 

 perty, we observe, on turning it slowly, besides its the colours. 

 common colours, many others, which are bright, change 

 very rapidly, and are distributed in small spots or 

 patches. A strong light is required, in order to 

 see this appearance distinctly, and it never occurs 

 in opaque or feebly translucent minerals. We observe 

 it in the diamond when cut, and in precious opal. 



IV, The Changeability if the Colours. 



When the surface of a mineral, which we turn in Thechange- 

 different directions, exhibits, besides its common colours, ability of 

 different bright colours, that do not change so rapid- the colours. 

 ly, are fewer in number, and occur in larger patches 

 than in the play of the colour, it is said to exhibit what 

 is called the changeability of the colours. The change- 

 ability of colour is seen only in particular directions, 

 the play of colour in all direction:-. 



We distinguish two kinds of this phenomenon. 



A. That which is observed by looking in .:ifferent po 

 sitions on the mineral, as in Labrador felspar. 



B. That observed by looking through it, as in the com- 

 mon opal, which shows a milk-white colour when 



* The most accurate delineations of colours are given in Syme's Wemerin Nomenclature of Colours, published in Edinburgh a few 

 years ago. 



