Dr. F. H. Hatch— Gem-Gravel, W. Coad of Africa, 109 



Gold. — An examination of the gold obtained by washing and now in 

 the London office of the Liberian Company shows that it has the usual 

 characteristics of the noble metal when obtained from alluvial sources. 

 It is fairly coarse, but not nuggety ; the grains are of irregular shape 

 and are usually somewhat flattened. The colour is a beautiful dark 

 yellow, due to the low proportion of silver, the fineness on assay being 

 971 per 1,000 parts. 



Kyanite. — This, the most abundant mineral in sample A and the 

 second most abundant in sample B, occurs in pale-blue to pale 

 yellowish-green glassy fragments bounded by faces of the prismatic 

 zone with predominant macro-pinacoid (100) and perfect cleavages 

 parallel to the same face. Many of the fragments are flecked with 

 minute black inclusions apparently of an iron-ore (magnetite ?). The 

 densit}^ was determined as 3'72. 



Corundum. — This mineral is abundant in sample A, but absent from 

 sample B. It occurs as cleavage fragments with no signs of rounding ; 

 colour, a dull pink with imperfect translucency. The basal plane (111) 

 shows the triangular reticulation of fine lines due to lamellar twinning 

 on the rhombohedron (100). The density was determined as 4-0. 



Garnet. — This, the most abundant mineral in sample B, is absent in 

 sample A. It is a blood-red variety, probably that known as pyrope. 

 The fragments are of an irregular shape, determined by the uneven 

 fracture and imperfect cleavage characteristic of the mineral, and 

 present no crystal faces. The density was determined as 3'98. 



Rutile. — This mineral is fairly abundant in sample A, but was not 

 found in sample B. The fragments present dominant faces of the 

 prism zone with vertical striation. The metallic-adamantine lustre is 

 a predominant characteristic. Fractured surfaces show a reddish 

 colour and there is a slight translucency at the edges. The density 

 was determined as between 4'1 and 4'4. 



Zircon. — A few crystals of zircon were found in both samples. 

 One or two are almost perfect crystals — the prism (110) terminated 

 by the pyramid (111). Colour, dark brown; lustre, vitreous. The 

 density was determined as 4-75. Some colourless crystal fragments 

 in sample B possessing strong double refraction and a high index 

 of refraction (greater than that of methylene iodide) appear to be 

 a special variety of this mineral. A goniometric measurement of the 

 angle between two adjacent faces gave 48°, which corresponds closely 

 to the angle (111) (110) = 47° 50'. 



Chromite. — This mineral is fairly abundant in sample B, in rather 

 small iron-black grains with sub-metallic lustre, giving a blackish- 

 brown streak. As a rule the grains are irregular with conchoidal 

 fracture or rounded, but one showed the spinel type of twinning. 

 Fusion with borax gave the characteristic chromium reaction. The 

 density was determined as 4-92. 



Ilmenite. — This mineral occurs in sample A in tabular iron-black 

 fragments with brilliant metallic lustre. Goniometric measurement 

 gave the following results : — 



111 : 100 = 57° 59' 

 111 : 311 = 61° 44' 

 which agree sufficiently closely with those of ilmenite. 



