Native gold is a shiny, yellow, metallic mineral that does not tarnish, and it leaves a shiny, golden-yellow streak when you rub it across a streak plate. If silver is present, the color and streak have a lighter shade. Pure gold is extremely heavy—its specific gravity is 19.3. Because it is malleable, this mineral will flatten into a thin sheet when hammered. It is ductile enough to be drawn out into wires. Gold is also soft—a pocket knife will scratch it easily. When it is to be used for ornaments and jewelry, gold is usually mixed with other metal, such as silver, copper, nickel, or palladium, to make it harder. The amount of gold that is present is then indicated by _carats_ (or _karats_). Pure gold is 24 carats. If you have a gold ring that has _14 K_ stamped inside it, you know that it is made of a mixture of 14 parts gold and 10 parts of other metal. Gold commonly occurs in nature as plates, scales, or grains. Some of the grains are large enough to be called _nuggets_. It also is found in a wire-like shape described as _filiform_, it occurs in a network, called _reticulate_, and it can have a branching and fern-like shape, described as _dendritic_. Gold is not often found as individual crystals. Several other minerals, such as pyrite, chalcopyrite, and mica, are sometimes mistaken for gold. None of these, however, is malleable and ductile, and none is nearly as heavy as gold. Pyrite and chalcopyrite have dark-colored streaks unlike that of gold. Mica cleaves so perfectly that it can be split into thin, flat sheets, but gold has no cleavage at all. The best places to look for gold are in areas near igneous rocks and along the creeks and rivers that drain these areas. It is thought that most gold originally was carried up from molten igneous rock by hot solutions. The solutions moved into cracks and other openings in nearby rocks and deposited the gold, commonly along with quartz. Later, some of these gold-bearing rocks weathered away. The gold that the rocks contained either remained at the spot or was washed into creeks and rivers. These transported accumulations of loose gold are called _placer deposits_. [Illustration: Placer gold in very small quantities has been found in some of the stream gravels of Texas.] No really important gold deposit has ever been found in Texas, although traces and small amounts have been reported in several areas. A little gold has been found in the Llano uplift area of central Texas. It occurs in quartz veinlets that cut through some of the Precambrian metamorphic rocks of Llano, Mason, northeastern Gillespie, and west-central Burnet counties. Many years ago, a small amount of gold was mined northeast of Llano in Llano County from the Heath mine. Some gold also has been found in sands and gravels along streams, such as along Sandy Creek and its tributaries, in parts of this Llano uplift area.