​Vanadinite is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals.  

Vanadinite is an uncommon mineral, only occurring as the result of chemical alterations to a pre-existing material. It is therefore known as a secondary mineral. It is found in arid climates and forms by oxidation of primary lead minerals. Vanadinite is especially found in association with the lead sulfide, galena. Other associated minerals include wulfenite, limonite, and barite.

Approximately 85% of the vanadium produced is used as ferrovanadium or as a steel additive.  The considerable increase of strength in steel containing small amounts of vanadium was discovered in the early 20th century.  From that time on, vanadium steel was used for applications in axles, bicycle frames, crankshafts, gears, and other critical components.

Why Collectors Like Apex Mine Vanadinite -

Mineralogical Record did a feature article on the Apex Mine, and its reputation rests heavily on the quality of its vanadinite and wulfenite specimens.

Apex Mine specimens usually have those caramel-red hexagonal prisms perched on sparkly white calcite are very photogenic and highly sought after.

Now closed & finite, the mine is no longer actively producing collector specimens, so most good pieces are from older collections or limited later finds. That gives them a bit of “classic locality” cachet.