Pebbles Introduction

The main chemical component of pebbles is silicon dioxide, followed by small amounts of iron oxide and trace amounts of manganese, copper, aluminum, magnesium, and other elements and compounds. These elements possess different pigments; for example, reddish pebbles are due to iron, blue pebbles to copper, purple pebbles to manganese, yellowish translucent pebbles are chalcedony (a silica gel), and jade-colored pebbles contain green minerals, etc. Because of the different types and amounts of these pigment ions dissolved in the silica hydrothermal fluid, pebbles exhibit a myriad of colors, ranging from black, white, yellow, red, dark green, to bluish-gray.