Agate

SiO,. Silica. Non-crystalline,translucent, variegated quartz, capable of taking a high polish. The colors sometimes shade gradually into each other, and are sometimes arranged in parallel bands. The differently colored portions are often affected differently by chemical reagents, and the natural colors can be materially changed by artificial means. Good agates are found in many parts of the U. S., especially ab. Lake Superior and at several points in the Rocky Mountains. Brazil and Hungary furnish large and fine stones, which are polished for market at Oberstein, Germany.