si·li·ceous 
(sĭ-lĭshəs)
(sĭ-lĭshəs)adj.
Containing, resembling, relating to, or consisting of silica.
[From Latin siliceus, of flint, from silex, silic-, flint.]
- circumstantial
- circumstantial evidence
- circumstantiality
- circumstantially
- circumstantiate
- circumstantiation
- circumstellar
- circumterrestrial
- circumvallate
- circumvallation
- circumvent
- circumventer
- circumvention
- circumventive
- circumventor
- circumvolution
- circumvolve
- circus
- circusy
- cire
- cirque
- cirrate
- cirrhosis
- cirrhotic
- cirri