This sand sample is from the Western coast of Ghana (#991 in my collection). The sand is coarse grained and is composed of several distinct and interesting components. Here is a short illustrated description of this sand sample.
This sand is pretty unusual because it is largely composed of lithic fragments. Most sands are composed of mineral fragments, majority of them being quartz of course. Quartz is present in this sample also but it is a relatively minor component. Lithic sands are immature sediments. It means that their source rocks are not far away. Volcanic rocks of bimodal character (basalt-rhyolite) are present on the coast in this particular case. Typically to ocean coasts in low latitudes, this sand contains many different biogenic grains. Most of them are clam shells and sea urchin spines.
Sand sample itself. Most grains are about 1 mm in diameter.
Sea urchin spines.
Clam shells.
Altered basalt (green color is a result of chloritization and epidotization).
Rhyolite fragments.
