The GemColony Blog
Practical guides for gem dealers, cutters and traders: pricing, treatments, memos, certificates and running a tidy stock room.
Gemstone inventory: spreadsheet or software?
When an Excel sheet is enough for a gem dealer, the signs it is not, and what to look for when you move to gemstone inventory software.
What is a gem memo, and how to manage stones on memo
A memo lets a dealer hand stones to another party without selling them. How memos work, the risks, and how to track them.
Heated vs unheated sapphire: what buyers should know
Most sapphires are heated. What heat treatment does, why unheated stones cost more, and why records and lab reports matter.
How to price a sapphire
The factors that move a sapphire's price: colour, clarity, size, origin, treatment and cut, and how to keep your prices consistent.
How to track weight loss in gem cutting
Cutting rough into a polished stone loses most of its weight. How to measure yield stage by stage and find where it is going.
How to issue a gemstone provenance certificate
What a provenance certificate records, how it differs from a laboratory report, and how to let buyers verify it.
How to value loose gemstones
A practical method for valuing loose stones: identify, grade, check treatment, compare sales and add margin.
Gemstone treatments explained: heat, filling, diffusion, irradiation and oiling
The common gemstone treatments, which stones they apply to, and how to record and disclose them correctly.
Padparadscha sapphire: what it is and how dealers record it
Padparadscha is a rare pinkish-orange sapphire. Why the name is contested, what labs say, and how to keep records straight.
Ceylon sapphire: Ratnapura, Elahera and where Sri Lankan stones come from
A dealer's guide to Sri Lankan sapphire: the main gem fields, how the stones are mined and what to record about origin.
Lab report vs provenance certificate: what each proves
A gemological report and a provenance certificate do different jobs. What each one proves and when buyers ask for them.
AI gemstone identification: what it can and cannot do
AI can speed up sorting and give a second opinion from photos, but it cannot replace a laboratory. Where it helps and where it does not.
The fields every gemstone inventory record needs
A checklist of the details to store for each stone: identity, measurements, treatment, origin, cost, photos and documents.
Why general ERP software struggles with gemstones
Odoo, Zoho and similar tools are built for products sold by quantity. Why unique stones, parcels and memos break that model.
What a gem memo agreement should include
The terms to put in writing when stones go out on memo: description, value, duration, risk, insurance and return. Not legal advice.
How to start a gem business in Sri Lanka
The roles in the Sri Lankan gem trade, the licences to check first, and the records to keep from day one. A practical starting guide.
Gem export from Sri Lanka: the process in plain terms
An overview of how gems are exported from Sri Lanka: the NGJA dealer licence, inspection, invoices and customs. Confirm current rules with the NGJA.
Ratnapura gem market: a guide for buyers and dealers
Ratnapura is Sri Lanka's city of gems. How the district's gem trade works, what is sold there and how to buy with confidence.
Beruwala and China Fort: the gem cutting and trading hub
Beruwala on Sri Lanka's south-west coast is a major cutting and trading centre. What happens there and how dealers keep track of stock.
Sapphire origins: Sri Lanka, Myanmar, Kashmir, Madagascar and more
Where sapphires come from, what each source is known for, and why dealers record origin only when it can be supported.
Ruby origins: Myanmar, Mozambique, Thailand and Madagascar
Where rubies come from, how sources differ, and what to record so origin and treatment stay attached to each stone.
Emerald origins: Colombia, Zambia, Brazil and Afghanistan
Where emeralds come from, how each source is described, and why treatment records matter as much as origin.