This is a Rock, Not a Slice of Cheesecake. This specimen from Central Nevada
Credit: Chelsea Thompson
Red agate and White Opal with Botryodial Chalcedony
Agateis a variety of chalcedony, acryptocrystallineform of quartz. Translucency, patterns of color, or moss-like inclusions may distinguish this stone from other forms of chalcedony. Agates can showa wide variety of vivid, multiple colors. These are principally the result of traces of oxides of iron, manganese, titanium, chromium, nickel, and other elements.
Opalis a white colored semi-precious gemstone of silicate mineral family recognised for its wonderful ‘play of colors’.
Chalcedonyis the form ofQuartzthat is compact and microcrystalline. It occurs in many different forms, colors, and patterns, and many varieties have been used as gemstones since antiquity.
