Natural Dimension Stone Standard – ANSI/NSC 373

Visit the NSF Listings Page to view the most up to date record of all natural stone companies
certified to ANSI/NSC373 Sustainable Production of Natural Dimension Stone

“Certified stone producers ensure architects, landscape architects and consumers that the natural stone for their projects has been produced in an economical, environmental and socially  responsible manner.”

NSC 373 earns recognition in US Green Building Council’s LEEDv4
and Living Building Future’s Living Building Challenge!

Read press release

News of this recognition has made positive impacts in the architectural community:

” This is amazing news. Thank you for sharing it and congratulations on

literally breaking new ground on responsible stone sourcing! Very cool stuff.”

Wide circles of green building media outlets have picked up this press release
and are reporting its message through their websites. 
Read progress report.


Visit the NSF Listings Page to view the most up to date record of all natural stone companies
certified to ANSI/NSC373 Sustainable Production of Natural Dimension Stone



The American National Standards Institute (ANSI) has recently published
ANSI/NSC 373 Sustainable Production of Natural Dimension Stone”  and Natural  Stone Council Chain of Custody standards.

Purchase the Standards

These standards have been developed to document and improve the  sustainability profile of natural dimension stone production.

The purpose of the Standard:

  • Recognizes and drives sustainability practices in the natural dimension stone industry.
  • Establishes a set of well-defined environmental, ecological, social responsibility and human health metrics through a multi-stakeholder, science-based approach, recognized by the green building movement as an indicator of leadership in sustainability performance.
  • Provides an important opportunity to educate key members of the design and building professions, end users, government, and environmental advocacy groups about the production of natural dimension stone products.
  • Uses a four-tiered rating system (Bronze, Silver, Gold or Platinum), creating a mechanism that differentiates natural dimension stone companies that demonstrate environmental leadership through commitment to sustainable operations and continued innovation.

Two additional components to ANSI/NSC 373 Sustainable Production of Natural Dimension Stone are chain of custody and conformance:

The Chain of Custody Standard establishes the rules by which stone originating from a certified quarry and then processed in a certified processing facility is documented as it passes through the supply chain to its end user.   The goal is to insure that the end user who purchases certified stone for a project actually receives verified, certified stone.

The Guidance for Conformance document provides guidance on how ANSI/NSC373 is to be interpreted and gives examples that best provide evidence of criteria compliance by the quarries and processors seeking certification, as well as for the third party entities who will verify compliance. The creation of the Guidance for Conformance document was directed by Jack Geibig of Ecoform, with a selected group of leaders from the process, which included pilot certification members TexaStone Quarries, Garden City, Texas and Lyons Sandstone, Lyons, Colorado.
Sample Worksheets available for reference.

How to Certify

To apply for certification, you must:

1.  PURCHASE THE STANDARD  Each certifying applicant MUST purchase the STANDARD and CHAIN OF CUSTODY documents. It is strongly recommended to purchase the GUIDANCE for CONFORMANCE document to assist your efforts. You may purchase individual documents or order a bundled package at a discounted price if you are a member of an NSC Affiliate association.

2.  CONTACT NSF or another third party verifying entity who will confirm purchase origination with the Natural Stone Council prior to initiating contract with the purchaser.

Sample Worksheets available for reference.

Unsure whether an ANSI/NSC 373 certification is within reach? Click here for a summary of its criteria and an example of the criteria scorecard.

Are you a member of a Natural Stone Council affiliate organization?  Contact your association executive for a coupon code giving additional discounts. Purchase the Standards

More About the Standard

Preview ANSI NSC373 Criteria and Scorecard

The purpose of the Sustainability Assessment for Natural Dimension Stone is to recognize sustainability practices in the natural stone industry – practices many members already follow but don’t document or promote. This voluntary standard will eventually give quarries and primary processing plants the ability to certify their operations (and subsequently their stones) as sustainable. Third party verification of conformance to a set of well-defined environmental, ecological, social responsibility and human health metrics will be required. To date, the stone industry has not been able to compete on a level playing field with other industries that already have a standard like this in place such as wood, tile and carpet.

In collaboration with the Natural Stone Council and Ecoform, NSF International (NSF) convened a Standards Committee for development of an American National Standard for the sustainable development aspects of dimensional stone production. The Standards Committee reviewed  Public Comments for action in accordance with accepted ANSI criteria.  Designated as NSC 373, the Standard is intended to offer the following benefits to the stone industry:

  • Establish a set of well-defined environmental and human health metrics recognized by the green building movement as an indicator of leadership sustainability performance.
  • Provide an important opportunity to educate key members of the green building movement, government, and environmental advocacy groups about the production of stone products.
  • Create a mechanism that rewards natural stone companies that demonstrate environmental leadership through commitment to sustainable operations and continued innovation.
  • Proactively address potential stone-related environmental and human health concerns in a multi-stakeholder, science based forum (i.e. radon, dust, etc.).
  • Harmonize national and international environmental requirements for stone quarrying and production.
  • Encourage transparent chain of custody reporting in support of LEED credits.
  • Create parity between stone and other competitive products covered by existing certification programs.

This Standard defines Environmentally Preferable Manufacturing Practices (EPMP’s) for the quarrying and manufacture of dimensional stone products, and establishes baseline requirements for EPMP’s applicable to all stone manufacturers and processors. Specifically, the standard defines criteria that consider the social, environmental, and human health impacts associated with the dimensional, natural stone product life-cycle including but not limited to the quarrying and manufacturing life-cycle stages. Because stone is quarried in countries around the world, the scope of the standard includes both North American and International quarries and processing facilities, and considers logistics and transportation issues during criteria development. The standard will assist in the determination of whether a dimensional stone product has been produced and transported in an environmentally preferable manner consistent with the principles of sustainability.

The standard focuses on North American based stone products and operations, but is developed with the participation and cooperation of the international stone community and is the basis for expanding to a proposed international-based ISO certification. Criteria define both environmentally preferable products and stone production operations.

NSF, NSC, and Ecoform sought volunteers for participation on an important Joint Committee. The Committee was a balanced composition of stakeholders including stone industry, government, environmental advocacy, academia, green building and design, and other relevant groups. NSF International administered the committee in accordance with its ANSI-accredited standard development process.

The standard was developed through an ANSI-based multi-stakeholder process, with an eye towards development of an ISO compliant standard with an international scope. The development process involved the creation of a core committee tasked with overseeing the development of draft criteria and performing technical research, and a larger group of stakeholders to review and ultimately approve individual criteria, a points system, implementation and the final standard.

Historical reference updates:

NSC 373 Natural Dimension Stone Standard was initially released for Public Comment between September 12th and November 12th, 2012.  Revision 2 of the Standard was released for a 45-day review period on April 8th, 2013. Revision 2 of the NSC 373 standard is now complete, with all comments having been considered and responded to in writing.


NSC COC v.1-Feb4,2014

NSC COC Comment Form



After many years and a great investment of both time and resources, it is time the Natural Stone Council and the natural stone industry tell the world about its sustainability standard.  This standard will assure architects, landscape architects, designers, contractors, owners and others that there is verifiable data to compare natural stone with other competitive products in this rapidly changing green building environment.

NSC is presently exploring a marketing campaign of simple and straight forward facts, told in a way that all of our audiences, including those in the stone industry, can understand its processes, implications and benefits.  Short video segments are being considered and could be available for industry use by the 4th quarter of this year.

Informational Videos:

9:15Natural Stone Council “Genuine Stone” by BillLevyProductions  ,

5:47 “Why NSC?” by BillLevyProductions , 


About NSF International
NSF International ( is well positioned to assist the stone industry in its goals of establishing consensus standards and a sustainability certification program for dimensional stone products. NSF International is a not-for-profit, non-governmental, third-party organization, and has been a leader in standards development, product testing and certification, education, and risk-management for the protection of public health and safety for over 60 years. While focusing on food, water, consumer products, and the indoor environment, NSF develops consensus national standards, provides third-party conformity assessment services, and provides learning opportunities through its Center for Public Health Education while representing the interests of all stakeholders. NSF is widely recognized for its scientific and technical expertise in the health and environmental sciences. Its professional staff includes engineers, chemists, microbiologists, toxicologists, and environmental health professionals with broad experience serving the needs of both public and private organizations.

About Ecoform
Ecoform ( is the leading technical analysis company in the United States that focuses on the environmental performance of companies and their products and processes. Founded in 2006, but based on the combined 50 year history of its practitioners working through a variety of corporate and university organizations such as The University of Tennessee’s Center for Clean Products, the team brings a unique mix of skills to help your company achieve corporate environmental and social responsibility. Ecoform takes pride in its ability to work confidentially with leading corporations across multiple industry sectors to provide critical information that can be used to shape corporate policy. With Ecoform’s insight your company will be in a position to lower its environmental footprint, enhance its market brand and public perception, and often save valuable financial resources at the same time. Whether you need something as specific as a detailed product Life Cycle Assessment or as general as an overall corporate sustainability report, we can help.