siliceo

Marble breccias are formed of angular pieces of highly crystalline limestone, united together by a siliceo-calcareous cement, containing usually an admixture of a hornblendic substance, and which is due to a particular action of adjacent masses or veins of iron ore.

Roman Mosaics Or, Studies in Rome and Its Neighbourhood Hugh Macmillan

In one place it is nearly white, almost a steatite; in another its color is barely diflferent, but it is more argillaceous and has a sort of oblique cleavage in addition to the lamination of the strata; again, it is light-gray, very talcose, and contains little nodular grains of quartz, is dark - gray and without the quartz, or the common red-and-white siliceo-magnesian shale that makes up so much of the eastern eijd of the chain.

Transactions of the American Philosophical Society 1771