Gemstone district

Montana Sapphire Deposits

Documented United States sapphire localities represented in gemological reference material.

Evidence statusPublished & sourcedLast reviewed August 17, 2026
OverviewGeologyGem relationshipsSources

Evidence-backed overview

The place, clearly defined

Documented United States sapphire localities represented in gemological reference material.

Geological context

How the occurrence is understood

Documented United States sapphire localities represented in gemological reference material.

Bidirectional relationships

Documented gemstones

Occurrence and production are separate claims. A production label is date-bounded and does not guarantee quality, origin determination, or market value.

Documented occurrence

Sapphire

Authoritative evidence documents this gem at the location; this does not by itself imply commercial production.

Production not assessed

Occurrence is documented, but production status has not been assessed.

Evidence[1]

Evidence ledger

Sources & verification

Sources are deduplicated across the geographic record. Current-production claims receive explicit review dates; a map point never substitutes for geological or production evidence.

  1. [1]
    Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley. Chart: Inclusions in Natural, Synthetic, and Treated Sapphire.

    Gems & Gemology · 2017

    View authoritative source