Definitions

1. adjective

containing or resembling silica, especially in the form of small crystals, or consisting largely of silica

“The siliceous sand was used to make glass.”

2. adjective

relating to or containing flint or other siliceous minerals

“The siliceous rocks were found in the area.”

3. noun

a siliceous substance, especially one used in glassmaking

“Siliceous materials were used in ancient glass production.”