Sagenite

Sagenite may refer to any of the following types of minerals with an acicular (needle-shaped) crystal habit. It is not a valid mineral species.^[1]

• A twinned, reticulated variety of rutile originally described in 1796 by Horace Bénédict de Saussure.
• Rutilated quartz, a variety of quartz with acicular inclusions of often golden-yellow rutile, first called sagenite by George Kunz in 1892.
• Sagenitic agate, a type of agate with acicular inclusions of another mineral such as anhydrite, aragonite, goethite, rutile, or a zeolite.^[2][3]
• Any other variety of quartz or chalcedony with acicular inclusions of another mineral.

• 
  Rutile sagenite from Brazil
• 
  Rutilated quartz sagenite
• 
  Sagenitic agate from the Oregon coast