What Diamex does

Diamex Inc, founded in 1976 and headquartered at 580 5th Avenue in New York's Diamond District, is a privately held B2B diamond manufacturer and trader serving wholesalers, retailers, auction houses, the U.S. State Department, and private customers. The company operates two service lines: Diamond Factory, which handles end-to-end manufacturing of polished diamonds from rough, plus recutting and repair of stones of all sizes, and Brilliant Finish, a proprietary polishing technology that improves surface finish from the Nano to the Angstrom range without weight loss, enhancing luster, dispersion, and scintillation and in some cases shifting stones to a higher color grade. Under President Ronnie Vanderlinden, who built the firm on 45+ years of industry experience and holds leadership roles at DMIA, IDMA, AGS, the Diamond Dealers Club of New York, and the 24 Kt Club, Diamex sources diamonds globally across the US, Far East, Canada, and Europe.

The company generates revenue through one-time sales of manufactured polished diamonds, trading of finished stones to wholesalers and retailers, professional services including appraisals, estate-sale support, and private-purchase facilitation, and fee-based Brilliant Finish polishing services to other diamond professionals. Pricing is quote-based and not publicly disclosed, reflecting the high-value, customized nature of each transaction. Go-to-market is relationship-driven and sales-led, relying on industry reputation, word-of-mouth referrals, and the founder's industry-association positions rather than active digital marketing, with a modest company website providing service information. Diamex's supply chain is OECD 5-Step compliant and RJC-Certified, a credential that protects access to major retail and government buyers. The company has 11–50 employees and no disclosed funding, no AI/ML capabilities, and no public revenue figures.

Name

Diamex

Legal name

Diamex Inc

Website

https://diamexinc.com

Company type

Private

Founded year

1976

Operating status

Operating

Headcount range

11–50 employees

Short description

Diamex Inc is a New York-based, 1976-founded diamond manufacturer and trader specializing in polished diamonds from rough, recutting, repairs, and proprietary Brilliant Finish polishing services, serving wholesalers, retailers, auction houses, the U.S. State Department, and private customers globally.

Ownership category

akta.pro rank

Product category

Diamond Manufacturing & Trading

NAICS

All Other Nonmetallic Mineral Product Manufacturing (32799)

SIC

Jewelry, Silverware & Plated Ware (3910), Wholesale-Jewelry, Watches, Precious Stones & Metals (5094)

akta.pro primary industry

Diamond Cutting & Polishing (Manufacturing) (CRAKAJAA)

akta.pro secondary industries

Polished Diamond Trading & Brokerage (CRAKAJAD), Rough Diamond Trading & Brokerage (CRAKAJAC), Made-to-Order Gemstone Sourcing & Custom Cutting Coordination (CRAKAHAF)

Keywords

• Diamond manufacturing services
• Diamond cutting polishing
• Rough diamond processing
• Diamond recutting repairs
• Diamond trading wholesale

Headquarters

HQ city

New York

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Personnel, Operations

Revenue model

1. Diamond Manufacturing: Manufacturing polished diamonds from rough diamonds, recuts, and repairs. The company evaluates each stone considering clarity, size, and brilliance to maximize beauty and value.
2. Diamond Trading: Buying and selling finished diamonds to both wholesalers and retailers.
3. Professional Services: Jewelry consultations, appraisals, estate sales services, and private purchase services.
4. Brilliant Finish Polishing Service: Premium diamond polishing service using proprietary technology that improves stone appearance without weight loss. Services provided to other diamond cutters and industry professionals.

Go-to-market motion2 records

Distribution channels1 record

Marketing channels2 records

Core offering

Diamex manufactures polished diamonds from rough diamonds, recuts and repairs stones of all sizes, and buys and sells finished diamonds to wholesalers and retailers. The company also provides jewelry consultations, appraisals, and acts as a trusted resource for estate sales and private purchases.

Product overview

Diamex operates as a diamond manufacturing and trading company offering two primary service lines: Diamond Factory (core manufacturing, recutting, and repair services) and Brilliant Finish (proprietary polishing technology). The Diamond Factory handles the complete lifecycle of diamonds—from rough manufacturing to finished product—while Brilliant Finish provides complementary advanced surface polishing that enhances the visual qualities of already-cut stones. Together, these services enable Diamex to offer end-to-end diamond value optimization for wholesalers, retailers, auction houses, and private customers.

Differentiator

Problem solved

Functional benefit

Brands

• Brilliant Finish: Diamond polishing technology that improves luster, dispersion and scintillation without weight loss. Uses natural processes to improve surface finish from Nano range to Angstrom range.

Products and services

• Diamond Factory

Quantifiable outcome

• Some stones shifted to next higher color grade after Brilliant Finish polishing

Named customers4 records

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature1 record

Partnerships

Eight partnerships are on record, tiered core.

• Diamond Manufacturers & Importers Association of AmericacoreOthersRonnie Vanderlinden serves as President/CFO of DMIA. This is a major industry association for diamond manufacturers and importers in America.
• International Diamond Manufacturers AssociationcoreOthersRonnie Vanderlinden serves as President of IDMA. This is the global association representing diamond manufacturers internationally.
• American Gem SocietycoreOthersRonnie Vanderlinden serves as Board Member of AGS, a prestigious gemological society focused on ethics and education in the jewelry industry.
• Diamond Dealers Club of New YorkcoreOthersRonnie Vanderlinden served as Former Chairman of the Board of the Diamond Dealers Club of New York, the major trading venue for diamonds in the US.
• 24 Kt Club of the City of NYcoreOthersRonnie Vanderlinden serves as Executive Board Member and Vice President of the 24 Kt Club, an elite industry organization in New York.
• 47th Street BidcoreOthersRonnie Vanderlinden serves as Executive Board Member of 47th Street Bid (Diamond District), the major diamond trading district in Manhattan.
• N. Gogolick & Son CorpcoreStrategic or Co-development PartnerDiamex Inc. and N. Gogolick & Son Corp conducted a joint Supply Chain Due Diligence. The assessment found no Red Flags, conducted per OECD 5 Step Guidelines. N. Gogolick & Son Corp is a supply chain partner in their responsible sourcing efforts.
• RJC Certified SupplierscoreOthersAll Diamex suppliers are RJC (Responsible Jewellery Council) Certified Members. This ensures ethical and responsible sourcing practices throughout their supply chain.

Scale indicators3 records

Recent moves4 records

Expansion highlights4 records

Direct peers

• Lazare Kaplan International: One of the oldest US-based diamond manufacturers and cutters, with operations spanning rough sourcing, cutting, and polished distribution—directly comparable to Diamex's core Diamond Factory activity.
• M. Fabrikant & Sons: Long-established diamond cutter and supplier of polished diamonds and jewelry, comparable in scale and business model to Diamex's manufacturing and wholesale trading operations.
• I. Hennig & Co: Global diamond trading and manufacturing firm handling rough and polished diamonds through offices in major diamond centers—comparable to Diamex's sourcing and trading activities.
• Leo Schachter Diamonds: Vertically integrated rough-to-polished diamond manufacturer supplying major retailers; directly comparable to Diamex's polished-diamond manufacturing and wholesale model.
• Rosy Blue: Globally active diamond manufacturer and dealer with cutting operations and a broad polished wholesale network—closely matches Diamex's B2B cutting and trading model.
• Dalumi Diamonds: Major international diamond manufacturer and supplier of polished stones to retailers worldwide, comparable to Diamex in cutting focus and global wholesale reach.
• Diarough N.V. Vertically integrated diamond manufacturer with rough sourcing, cutting, and polished distribution—a comparable full-lifecycle diamond manufacturer.
• Kiran Gems: One of the world's largest diamond manufacturers with end-to-end rough-to-polished operations, comparable in core manufacturing activity though larger in scale.

Broad incumbents

• De Beers Group: Dominant integrated diamond miner, sorter, and marketer through De Beers Ignite and Forevermark; competes broadly in polished supply but operates at vastly larger scale and upstream.

Emerging players

• Brilliant Earth: Vertically integrated jewelry retailer with strong focus on ethical sourcing and lab-grown diamonds—an emerging player addressing adjacent customer demand that intersects with Diamex's natural-diamond service offering.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Diamex