Catuṣkoṭi (Pvt) Ltd · Ratnapura & Colombo · Sri Lanka
Colour sets a gem’s price. Ceylon origin adds to it. We study colour as scientists, and we own the ground it comes from.
Illustrative · how a blue sapphire passes light across the visible spectrum
Colour
Colour is most of what a coloured gem is worth, yet the trade still describes it in words: royal, cornflower, “a bit inky”. And a gem’s colour shifts with the crystal’s orientation, its inclusions, the cut and the light. It is one of the hardest things in colour science to pin down. We have spent careers on colour, and it shapes how we choose rough, how we cut it, and how honestly we describe every stone.
Two blues anyone might call royal. Illustrative swatches.
The trade’s colours
Pigeon’s blood and royal blue are the two most valuable colour names in ruby and sapphire. Yet no lab publishes numbers for them. Each judges by eye against its own master stones, and their definitions differ.
Ruby
Estimated from GIT’s pigeon’s blood reference stones
A vivid red with no blue or brown modifier, lit from within by red fluorescence: high chromium, low iron.
SSEF · Gübelin: untreated, strong fluorescence. GRS: heated stones can qualify. Gübelin “Crimson Red”: the same colour, with weak fluorescence.
Sapphire
Estimated from SSEF’s royal blue master set
A saturated, vivid blue, pure or with a very slight purplish tint, judged against master stones.
SSEF · Gübelin: untreated stones only. GRS: its own “GRS-type” range; conventional heating not excluded.
Same words, different rules. A heated ruby can be GRS-type “pigeon’s blood”, but never “pigeon blood red” at SSEF or Gübelin.
That’s why we study colour so closely.
Approximate colours, taken from the reference stones labs publish. Real stones glow in a way no screen can show. Sources: GIT, SSEF, Gübelin, GRS.
Source
A fine Ceylon stone, unheated, from a known pit, is worth more, and it’s harder to fake.
Where
On our own land in the Ratnapura district. Not a dealer’s packet.
How
Licensed teams, open auctions, and a written settlement after every sale.
Cut
Colour first, weight second.
Treatment
Heated or not, we tell you. We were there.
Certified
Lab reports for fine stones.
Work with us
01 · For mining teams
Licensed, experienced teams can work our gem-bearing land in the Ratnapura district on a revenue share agreed upfront.
02 · For dealers
Natural Ceylon sapphire, spinel, chrysoberyl and more, from our own mines, to the trade in Colombo and abroad.
03 · For industry
Where colour decides whether a batch is accepted, we set the standard and the method with you, and advise on colour and process chemistry.
Why colour?
Sasanka Bandara spent his career making colour measurable: in thread at Coats, in apparel at MAS Brands and Brandix, and in tea with Huey, the instrument he built. Every industry had the same argument. Is this the right colour?
Then he looked at his own family’s gems. The thing that set their price, their colour, was still judged by eye.
Catuṣkoṭi is what he did about it. Measuring gem colour is his long-term research; for now, it guides how we choose and cut.
Second generation of the family gem-mining business · BSc (Hons) Chemistry, University of Colombo · MBA, University of Sheffield · Advanced Management Program, Columbia Business School
Contact
Land, rough, colour, or a question we haven’t thought of. We reply to every message.