- A chalcedony that occurs in bands of different colors and is used as a gemstone, especially in cameos and intaglios.
- A variety of quartz, closely allied to agate, characterized by a structure in parallel bands differing in color or in degree of translucency: in the better kinds the layers are sharply defined and the colors white with black, brown, or red.
- An infiltration of pus between he layers of the cornea, resembling a nail.
- In <em>conchology</em>: The piddock, <em>Pholas dactylus.</em>
- A razor-shell; a bivalve of the family <em>Solenidæ.</em>
- Deep, jet-black.
- Chalcedony in parallel layers of different shades of color. It is used for making cameos, the figure being cut in one layer with the next as a ground.
- Same as Mexican onyx.
- A deep jet-black color.
- a banded variety of marble or calcium carbonate resembling onyx. It is obtained from Mexico in various colors ranging from white to deep black.
- A banded variety of <xref>chalcedony</xref>, a <xref>cryptocrystalline</xref> form of <xref>quartz</xref>.
- a chalcedony with alternating black and white bands; used in making cameos