First Appearance Of
Avengers #66 (1969). Roy Thomas and Barry Smith. Ultron-6's reveal as an adamantium-bodied threat.

1st Appearance

First Appearance of Adamantium

Avengers #66

July 1969 · Marvel · Silver Age

Roy Thomas and Barry Smith's 1969 fictional metal. Adamantium is a steel-and-iron alloy that is virtually indestructible once it sets. Wolverine's bones and claws are coated or laced with adamantium; Ultron's body is constructed from it. One of Marvel's most-cited fictional materials.

Key Issue

Created by Roy Thomas · Barry Smith

By Atomm Updated

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Marvel Comics Concept The unbreakable metal alloy.

Adamantium first appears in Avengers #66 (July 1969), Roy Thomas and Barry Smith, as the metal Ultron-6's body is made of. The alloy is virtually indestructible once it sets. Wolverine's bones and claws are coated or laced with adamantium; the Weapon X program (Marvel Comics Presents #72-84, 1991, Barry Windsor-Smith) is the canonical bonding origin. Adamantium has been adapted extensively in X-Men and Wolverine films.

Firsts Timeline

  1. Avengers #66 cover
    First Appearance July 1969

    Avengers #66

    By Roy Thomas, Barry Smith

    Roy Thomas writes; Barry Smith pencils. Adamantium is introduced as the metal Ultron-6's body is constructed from. The framing establishes the alloy as virtually indestructible once it sets, with the manufacturing process requiring extreme conditions to manipulate.

  2. Wolverine's Adamantium Skeleton October 1979

    X-Men #126

    By Chris Claremont, John Byrne

    Wolverine's adamantium skeleton becomes a defined element of his mythology. The Weapon X program (introduced more fully in Marvel Comics Presents #72-84, 1991, by Barry Windsor-Smith) provided the canonical adamantium-bonding origin.

What adamantium is

Roy Thomas and Barry Smith introduced adamantium in Avengers #66 (July 1969) as the metal constituting Ultron-6’s body. The framing positioned the alloy as virtually indestructible once it sets, requiring extreme manufacturing conditions. The concept gave Marvel a recurring ‘unbreakable material’ McGuffin that subsequent writers used across decades.

Wolverine’s adamantium skeleton became canonical across the late 1970s. Chris Claremont and John Byrne defined the framework in X-Men #126 (October 1979) onward; the Weapon X program in Marvel Comics Presents #72-84 (1991) by Barry Windsor-Smith established the canonical bonding origin. Wolverine’s adamantium claws and bones have been the most-recognized adamantium application since.

Collector context

Avengers #66 trades in the high three to low four figures at CGC 9.4 and above. The book’s adamantium-debut value is folded into the broader Avengers Silver Age run pricing.

Frequently asked questions

The questions readers and collectors ask most.

What is adamantium's first appearance?

Avengers #66 (July 1969), Roy Thomas and Barry Smith. Ultron-6 is the first character whose body is made of adamantium. Wolverine's adamantium skeleton becomes a defined element later (X-Men #126, October 1979 onward).

How is adamantium different from vibranium?

Adamantium is virtually indestructible once it sets; vibranium absorbs kinetic energy. Both are fictional Marvel-Universe metals with different properties. Captain America's shield uses a vibranium-steel alloy; Wolverine's claws are adamantium. The two materials serve different storytelling functions.

Is Avengers #66 valuable?

Modestly. CGC 9.4 trades in the high three to low four figures. The book is recognized as adamantium's first appearance and as part of the Roy Thomas Avengers run. Wolverine-related collector demand has kept the book's market position stable.

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