Ceylon Sapphire

Ceylon stopped existing when the island became Sri Lanka. Dealers kept the old word because it was already doing commercial work, and nobody in this trade retires a word that sells. A laboratory report says Sri Lanka; the invoice says Ceylon. Same island, same gem gravels — and neither word tells you what sets the price, which is whether the stone has been in a furnace.

The gravels

Most of the island’s sapphire comes out of illam, the gem-bearing gravel lying under the paddy soil and river alluvium of the southwest, and again in the Elahera belt at the centre. Around Ratnapura and Elahera men still work narrow timbered pits, hauling the gravel up and washing it by hand in a basket. This is secondary deposit: the stones did not form there. They weathered out of metamorphic rock and travelled, and badly fractured material broke up on the way, so what survives in the gravel tends to be sound. The same basket gives up spinel, chrysoberyl, garnet and zircon alongside the corundum, which is why a Sri Lankan dealer opens four papers before he opens the one you asked for.

Why Ceylon runs bright

Blue in sapphire comes from iron and titanium sitting adjacent in the lattice, passing an electron between them. Iron does other things. On its own it can push a stone yellow, and where iron passes charge between its own two states it darkens the blue and, in quantity, closes a stone up. Sri Lankan corundum is metamorphic and comparatively poor in iron, which is why classic Ceylon blue arrives lighter in tone and stays open, quick with light. Basalt-related sapphire — the Australian and Thai material — carries far more iron and reads inky by comparison.

That is also the distinction between Ceylon and the velvet the Kashmir name is bought for. Kashmir’s look comes from a fine dispersion of microscopic inclusions that scatters light and softens the blue; Ceylon returns light instead of scattering it. Two different optical events, neither of them better. A buyer who wants Kashmir’s velvet will rarely find it in a Sri Lankan stone, and where a Sri Lankan stone approaches it, that is because the silk has been left in place.

Ceylon rough is also strongly zoned, in straight bands of blue against near-colourless. The cutter orients a zone low in the stone so the colour spreads across the face, which is why you judge the colour face-up, in daylight, and go to the side of the stone to find the zoning that produced it. Burmese stones out of Mogok run a deeper, rounder blue. Madagascar’s Ilakaka gravels are geologically close enough to Sri Lanka’s that finished stones can sit almost on top of each other in the hand. I work all three. Separating them afterwards is trace-element chemistry and inclusions read by a laboratory, and it stays an opinion.

Geuda, and what heat was invented to do

Geuda is the Sinhalese name for milky, semi-transparent corundum carrying too much fine rutile silk to sell as a gem. The titanium is already in the stone, locked up in the silk. Taken high enough for long enough, the silk dissolves, the titanium goes into solution beside the iron, and, in a reducing atmosphere and with luck, the material comes out of the furnace blue and transparent. Plenty of it does not. Thai burners industrialised the process, and blue sapphire has never been scarce in the same way since; who worked it out first is still argued between Chanthaburi and Ratnapura. Heat is permanent, stable, cheap against what it adds, and legitimate when disclosed. It is also why the overwhelming majority of blue sapphire in the market has been treated, and why unheated is a price rather than a compliment.

What the report will and will not say

Nobody calls heat by eye. A laboratory reads the inclusions — melted or snowballed silk, discoid tension fractures around zircon crystals, fissures that have healed glassy — and supports the reading with spectroscopy. Low-temperature heating leaves less behind, which is where careful reports hedge and where two laboratories can disagree. Diffusion is a heavier matter, and laboratories state it separately. If you are unsure what your document is telling you, read the report properly before you read the price.

Royal blue and cornflower belong to the same family as pigeon’s blood: colour appellations, granted by a laboratory to stones that clear a threshold of saturation and quality. They say nothing about origin. What they imply about treatment depends on the laboratory — SSEF reserves these terms for unheated stones, while GRS will grant them to heated material with the heating stated separately. A Madagascan stone can be royal blue, a Ceylon stone cornflower. Most of the time, though, the words reach me from a seller who awarded them himself, ahead of any laboratory and ahead of the stone.

Ceylon is a place, not a grade. I buy the stone first, and let the country be the last line on the invoice.