Sagenite

Appearance
Sometimes called "sagenite", quartz crystals which are included with "needle like" rutile crystals are common and are quite attractive. Other common attractive inclusions found are tourmaline, gold, silver, pyrite and goethite.

It is sometimes found as a needle-like inclusion in some gemstones, e.g. Sagenitic quartz and sagenite. Some transparent specimens are used in jewelry, occasionally being faceted or, when opaque, cut en cabochon.

Sources -- Brazil, George, Arkansas, North Carolina, other locations. Usually found as needle-like crystal inclusions in quartz (rutilated quartz) or agate (sagenite) and in many other materials.

The interior of the geode can be encrusted with amethyst or quartz crystal. Banding found in Plume Agate, Sagenite, Thunderegg, and Tube Agate is caused by silicate (green) iron oxide or limonite (red), and is referred to as banded agate, ...

See also: Quartz, Gemstone, Rutilated, Stone, Rutilated quartz