Henley's Twentieth Century Formulas, Recipes and Processes. Various

      Gold Alloys:

      Colored Gold Alloys.

      —The alloys of gold with copper have a reddish tinge; those of gold with silver are whiter, and an alloy of gold, silver, and copper together is distinguished by a greenish tone. Manufacturers of gold ware make use of these different colors, one piece being frequently composed of several pieces of varying color. Below are given some of these alloys, with their colors:

	Gold	Silver	Copper	Steel	Cadmium
I.	2.6	1.0	—	—	—
II.	75.0	16.6	—	—	8.4
III.	74.6	11.4	9.7	—	4.3
IV.	75.0	12.6	—	—	12.5
V.	1.0	2.0	—	—	—
VI.	4.0	3.0	1.0	—	—
VII.	14.7	7.0	6.0	—	—
VIII.	14.7	9.0	4.0	—	—
IX.	3.0	1.0	1.0	—	—
X.	10.0	1.0	4.0	—	—
XI.	1.0	—	1.0	—	—
XII.	1.0	—	2.0	—	—
XIII.	30.0	3.0	—	2.0	—
XIV.	4.0	—	—	1.0	—
XV.	29.0	11.0	—	—	—
XVI.	1.3	—	—	1.0	—

      Nos. I, II, III, and IV are green gold; No. V is pale yellow; Nos. VI, VII, and VIII bright yellow; Nos. IX and X pale red; Nos. XI and XII bright red; Nos. XIII, XIV, and XV gray; while No. XVI exhibits a bluish tint. The finished gold ware, before being put upon the market, is subjected to a special treatment, consisting either in the simple pickling or in the so-called coloring, which operation is conducted especially with alloys of low degree of fineness, the object being to give the layers a superficial layer of pure gold.

      The presence of silver considerably modifies the color of gold, and the jeweler makes use of this property to obtain alloys of various shades. The following proportions are to be observed, viz.: {67}

	Color of Gold	Gold per 1,000	Silver per 1,000	Copper per 1,000
I.	Green	750	250	—
II.	Dead leaves	700	300	—
III.	Sea green	600	400	—
IV.	Pink	750	200	50
V.	English yellow	750	125	125
VI.	English white	750	150	100
VII.	Whiter	750	170	80
VIII.	Less white	750	190	60
IX.	Red	750	—	250

      Other colored gold alloys are the following:

      X. Blue.—Fine gold, 75; iron, 25.

      XI. Dark Gray.—Fine gold, 94; iron, 6.

      XII. Pale Gray.—Fine gold, 191; iron, 9.

      XIII. Cassel Yellow.—Fine gold, 75; fine silver,