Our Natures-Illusions collection has both geodes and banded agate slices.
A geode typically begins when a cavity forms in a rock, Geodes can also form in sedimentary rocks such as limestone or sandstone. When the geode forms, its outside crust will be older than the crystals inside. Most geodes have interiors made of either quartz or calcite. Quartz crystals are silicates. Calcite’s main ingredient is calcium carbonate. Calcite with magnesium and a trace of manganese forms a nice pink dolomite layer, while iron in silicate accounts for the purples of amethyst. When a geode was close to a lot of heat, that could change the color. Geode rocks contain iron, magnesium, sulfur or a host of other elements. Geodes that have been filled completely over the years may exhibit various unique designs of the material that have been inside them. Some of the more dynamic specimens are coming from Brazil. Geodes can be found all over the world. Areas with the most geodes, however, tend to be deserts, volcanic ash beds, or areas with plentiful limestone.
In our Sliced Geodes series, we have many samples of front viewing and back light point source lighting to show off the translucencI of these specimens.
View our blog on Banded Agate for more details, also.
We also have Crazy Lace Agate to mix it up!