International gemstone mining, concession development and marketing
Green Ngoria is involved in international gemstone mining, concession development and direct marketing of precious colored stones.
The company owns two gemstone mines: one in Kenya and one in Tanzania. Both sit within the same disciplined operating framework as our gold business — qualified engineers heading each technical site, and environmental stewardship held to strict standards.
We handle both rough mineral crystals and certified cut stones, marketing to international buyers in the global gemstone trade with complete chain-of-custody traceability.
- Company Mines
- 2 Concessions (Kenya & Tanzania Assets)
- Varieties
- 5 Precious Species (Tanzanite, Tsavorite, Sapphire, Ruby)
- Grading Framework
- GIA Standard (Color, Clarity, Cut & Carat)
- Traceability
- 100% Provenance (Direct Mine-to-Market)
Gemstone Mining & Mineral Properties — Technical Portfolio
Authentic high-resolution documentation from Green Ngoria operations, field sites, and technical delivery across East Africa. Click any photo to zoom in up to 2.5x with full pixel clarity.
Cut Tanzanite Parcel
Cut Tanzanite parcel graded for international buyers.
Faceted Blue Sapphire
Faceted Blue Sapphire gemstone exhibiting vivid saturation.
Ruby in Matrix
Natural Ruby crystal specimen in host mineral matrix.
Green Tsavorite Rough
Rough Green Tsavorite garnet crystal from Kenyan concession.
Rough Tanzanite Specimen
Uncut rough Tanzanite crystal directly from mine extraction.
Technical Scope & Certified Deliverables
Gemstone Varieties Handled
- Tanzanite (Zoisite Species)Trichroic Blue-Violet
Mined from Tanzanian concession; rough crystal specimens and calibrated faceted gemstones.
- Tsavorite Garnet (Grossular Species)Vivid Emerald Green
Mined from Taita Taveta belt in Kenya; exceptional brilliance and untreated natural color.
- Corundum (Sapphire & Ruby)Mohs Hardness 9.0
Fine blue sapphires and deep red rubies extracted from pegmatite and metamorphic host rocks.
Scope of Work — Official Company Profile
- International gemstone mining and underground development
- Two company-owned gemstone mines — one in Kenya, one in Tanzania
- Optical sorting, sorting by refractive index, and rough crystal grading
- Precision lapidary cutting, faceting, and polishing to international standards
- Marketing to regional and international gemological buyers
- Acquisition and valuation of new gemstone-bearing properties in East Africa
Phase-by-Phase Execution Pathway
Reef Delineation & Tunneling
Follow gem-bearing pegmatite and hydrothermal veins with controlled non-explosive extraction.
- Reef Geological Log
- Recovery Batch Record
Sorting, Grading & Valuation
Clean, sort rough crystals by color, clarity, and facet potential under gemological daylight.
- Gemological Sorting Sheet
- Carat Weight Register
Faceting & International Export
Cut and polish top-grade rough into certified gemstones with official Ministry of Mining export permits.
- Export Royalty Receipts
- GIA Standard Appraisal
Design Criteria & Technical Parameters
| Parameter / Specification | Standard Design Criteria | Application & Engineering Notes |
|---|---|---|
| Hardness Range (Mohs Scale) | 7.0 – 9.0 (Garnet to Corundum) | Ideal for fine jewelry and collectors |
| Grading Standard | 4Cs (Color, Clarity, Cut, Carat) | Master color sets used for calibration |
| Treatment Policy | 100% Disclosure of any thermal treatment | Guaranteed natural untreated Tsavorite and Sapphire |
Products and Sub-Divisions
Materials Handled
Rough crystals and precision-cut gemstones marketed to international gem merchants.
- Tanzanite (Rough & Cut parcels)
- Blue Sapphire (Vivid royal blue)
- Natural Ruby (Matrix & Faceted)
- Green Tsavorite Garnet (Taita Taveta origin)
- Green Tourmaline and Chrome Tourmaline
- Collector mineral specimens and rough lots
Standing Quality & EHS Commitments
- Health, Safety & Environment
- Environment, Health and Safety is given absolute priority in all projects the company undertakes, adhering strictly to NEMA EMCA Cap 387, OSHA 2007, and environmental mining regulations.
- Independent Quality Control
- Recognised quality-control institutions and accredited materials consultants are contracted to perform batch testing that verifies high product quality on every site.
- Regional Delivery Footprint
- Green Ngoria operates across Kenya, Tanzania, Uganda, Rwanda, Burundi, with corporate headquarters at Tatu City, Kijani Ridge, Nairobi.
Frequently Answered Questions
How do international buyers purchase gemstone parcels from Green Ngoria?
We accommodate private viewing at our Nairobi corporate office or arrange insured international courier delivery with statutory export clearances.
Are all gemstones supplied with export documentation and royalty receipts?
Yes. Every parcel is exported with verified mining provenance, mineral dealer licences, and official royalty documentation.
- Gold Mining & Mineral ExtractionMining Operations
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Enquire About Gemstone Lots
Reach our customer care on +254 704 160 431 or email customercare@greenngoria.com — or send the details through the request for quotation form and our engineering team will respond with a full proposal.
Customer care & enquiries
Director lines & emails: Leadership Profiles →
Tatu City, Kijani Ridge, Nairobi, Kenya