Material source record

Concord Gray Granite

Source checked 25 Sept 2026

Full-size source sample visually checked against its named material page. Site-owner approval; photographer and producer-issued license are not documented.

View sample at source Open sample photograph

Catalogue reference. Confirm the current range and finish with the supplier.

Material sources

Swenson: Concord Gray and quarry history

Swenson curbing

MSHA mine information

Light gray granite from Rattlesnake Hill in Concord, New Hampshire, with a tight grain and small brown flecks. Historically known as Swenson Gray.

Listed supplier: Swenson / Polycor
Quarry / operation: Rattlesnake Hill, Concord, New Hampshire — Swenson Granite Works
Location: New Hampshire
Color families: Gray
Supply route: Dimension stone and curbing. Confirm current block availability, sizes and fabrication requirements.
Listing source: Producer documentation · source checked 25 Sept 2026
Photograph: Sourced photograph · checked 2026-09-25

MSHA: Active · Mine ID 2700083

MSHA record details

SWENSON GRAY QUARRY

Snapshot: 18 September 2026. Mine source record 2700083 · Look up this ID at MSHA · Status effective 29 December 1982

Regulatory classification; confirm current supply separately.

Material-to-mine association supported by the linked sources.

Mine source record

Independent source checks

U.S. material origin: VERIFIED
Material identity: VERIFIED
Producer relationship: VERIFIED
Quarry relationship: VERIFIED
Quarry location: VERIFIED
Operating record: VERIFIED
Photo source: VERIFIED
Photo permission: SITE_OWNER_APPROVED
Technical data: REVIEW

Each check stands on its own. A photo or coordinate review does not change a confirmed material identity or producer relationship. Operating records do not guarantee current inventory.

Documented capabilities

Dimensional stone: Yes
Source 1 · Source 2

Restoration and matching

Historical material names: Swenson Gray
Source
Documented applications: Library of Congress; New Hampshire State House; Concord Public Library
Source

Related producer groups

Polycor

Source-described uses

Landscape & site stone

Uses described by the producer. This is not a finding of suitability for a particular assembly or project.

Application source

Origin evidence

Extraction country: USA — verified[1]
Extraction state: New Hampshire — verified[1]
Quarry / operator: Rattlesnake Hill, Concord, New Hampshire — Swenson Granite Works[1]
MSHA Mine ID: 2700083[2]

Sources (2)

Source 1 · extraction country, extraction state, quarry / operator
Source 2 · msha mine id

Confirm before specifying

Ask the supplier about current availability, material range, fabrication and test data for your application. A listing or MSHA status does not establish supply readiness.

Open producer material page

Supplier technical resources

Published specification summaries are available; a traceable material-specific laboratory report has not been verified.

Swenson documents the Concord Gray / Swenson Gray identity and Concord quarry. MSHA records the quarry operator as Swenson Granite Company LLC, controlled by Polycor.