=2–1= Discovery: “No lode claim shall be located until after the discovery of a vein or lode within the limits of the claim, the object of which provision is evidently to prevent the appropriation of presumed mineral ground for speculative purposes to the exclusion of bona fide prospectors, before sufficient work has been done to determine whether a vein or lode really exists.” (43 C.F.R. 3841.3–1) Obviously, then, the staking and recording of a claim without a discovery of mineral is to no avail, except that a discovery made prior to intervening rights perfects the location. A claimant diligently trying to make a discovery will generally be protected. Except for the minerals covered by the Leasing Act (1920), and common varieties which may be acquired under the Materials Act (1947 and 1955), “Whatever is recognized as a mineral by the standard authorities, whether metallic or other substance, when found on public lands in quantity and quality sufficient to render the lands valuable on account thereof, is treated as coming within the purview of the mining laws.” (43 C.F.R. 3812.1) Whether a mineral should be located as a lode or placer claim depends on the nature of the deposit. Lodes are deposits of mineral in place, regardless of their origin. The mineral must be firmly contained or embraced in solid rock. This includes veins with distinct hanging and foot walls, replacement deposits in sedimentary formations, ancient stream channels now consolidated in sandstones, such as the uranium deposits of Wyoming, and disseminated deposits such as the copper porphyries of Arizona. On the other hand, mechanical deposits of minerals such as gold contained in the gravels of stream beds and alluvium deposits are properly located as placer claims. However, certain rock types, such as marble and perlite while mineral in place, are properly located as placers since the Act of 1892 provided for locating building stone under the placer mining laws. Included are bedded minerals not contained in rock in place, such as bentonite. The discovery requirements for a lode claim are that the mineral must be in place. A discovery of float (a loose piece of ore from a vein) is insufficient. Merely a trace of mineral is insufficient. Discovery by geologic inference is insufficient. There must be an actual and physical exposure of a lode. The discovery must be on vacant public domain, which includes patented surface lands with minerals reserved to the United States.