(adjective) difficult for one of ordinary knowledge or intelligence to understand
(adjective) having an often intentionally veiled or uncertainmeaning
(adjective) being beyond one's powers to know, understand, or explain
Definitions for Silica
(noun) a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth 's crust as quartz or cristobalite or tridymite or lechatelierite