This invention relates to the preparation and treatment of caoutchouc and gutta-percha, either alone or in combination, for the purpose of producing a new manufacture or composition, applicable to various uses where hardness, strength and durability are required. The composition designed to be produced, will possess some of the characteristics of horn, ivory, jet, and may, according to the color imparted to it, be employed in place thereof; or it may be used as a substitute for costly woods, and be applied to furniture in the form of veneer. In treating caoutchouc (India-rubber) for this purpose, it is combined with sulphur,—the best proportion being about equal parts, by weight, of each ingredient. By combining sulphur in this proportion, with the caoutchouc, and subjecting the compound to the curing operation, (hereafter to be described) a hard substance will be produced, but a still better result will be obtained by the introduction of magnesia or lime, or of carbonate, or sulphate of magnesia, or carbonate or sulphate of lime, or calcined French chalk, or other magnesian earth, into the composition, in which case, the following proportions will be found highly advantageous, viz.; one pound of caoutchouc, half a pound of sulphur, and half a pound of magnesia, or lime, or carbonate or sulphate of magnesia, or carbonate or sulphate of lime, or calcined French chalk, or other magnesian earth. The proportions specified in both of these compounds, may be considerably varied without materially changing the result; but in no case is it desirable to use a much less quantity of sulphur than four ounces to every pound of caoutchouc. With either of these compounds just described, gum lac, or gum shellac, may be combined to great advantage,—say, in the proportion of from four to eight ounces of gum lac to every pound of caoutchouc. Rosin, oxides or salts of lead or zinc, of all colors, and other similar substances, both mineral and vegetable, may be added in small quantities, to either of the compounds, for the purpose of imparting a polish, or a color thereto, and for making the mixture work more easily; but no precise rule for these additions can be given; nor, indeed, is it necessary, as the taste and judgment of the operator will be his guide in this particular. The compounds produced according to the above plans, are next treated in the manner to be presently described; but, as this process is equally applicable to the treatment of other compositions included in this invention, the patentee first explains of what these compositions consist. When using gutta-percha in lieu of India-rubber, the inventor takes certain proportions of gutta-percha, sulphur and magnesia, or lime, or a carbonate, or a sulphate of magnesia or lime, or calcined French chalk, or other magnesian earth, and mixes them in a convenient manner.