Rockhounding Events in North Carolina
Streak: Golden, Yellow
Hardness: 2.5 – 3
Chemical Formula: Au
Native gold is an element and a mineral. It is highly prized by people because of its attractive color, its rarity, resistance to tarnish, and its many special properties – some of which are unique to gold. No other element has more uses than gold. All of these factors help support a price of gold that is higher than all but a few other metals.
Trace amounts of gold are found almost everywhere, but large deposits are found in only a few locations. Although there are about twenty different gold minerals, all of them are quite rare. Therefore, most gold found in nature is in the form of the native metal.
Granite is the most common igneous rock in Earth’s continental crust. Granite can be found all around you in countertops, tiles, monuments, and more.
Granite is made up primarily of feldspar, quartz, and mica, with feldspar being the most prominent. Feldspar is usually white gray, pink, or red in color and features a visible cleavage pattern. The mica found in granite can include muscovite, biotite, or both.
Granite is formed by slowly cooling molten rock material. Because the process is so slow, the crystalline structures of the minerals that make up granite are able to grow quite large. Over time, granite is uplifted and revealed on the Earth’s surface via the erosion of overlying sediment.
Hardness: 7.5 – 8
Chemical Formula: Be₃Al₂SiO₆
Emerald is a gemstone and a variety of the mineral beryl colored green by trace amounts of chromium and/or sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness is classified as generally poor.