The geochemistry of agate and chalcedony in volcanic rocks represents an intricate record of silica precipitation and crystallisation processes occurring under variable thermal and chemical conditions ...

Chalcedony includes minerals like agate, onyx, jasper, and heliotrope. Chalcedony has a waxy lustre and is usually translucent to opaque. Key characteristics of Chalcedony include its hardness (around ...

Mineral deposits can create markings that look like forests or mountains, and experts say each stone is distinctive. By Jill Newman When Tarun Adlakha displays a dendritic agate, with its finely ...

Agatized Coral hunting is becoming one of my absolute favorite things to do... beautiful colors, geodes, bubbly botryoidal agate... what else could you ask for?! Finding a fossil/gem/mineral all in ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. NMNH - Anthropology Dept.