Reading a Ruby in Poor Light

The first ruby I overpaid for was shown to me under a tungsten lamp in Chanthaburi. The stone read a full grade better than it was. The lesson cost me four thousand dollars, and it was cheap at the price.

Warm light flatters red stones. Burmese ruby fluoresces, and an incandescent bulb wakes that fluorescence while hiding the brown a trained eye would catch in daylight. A seller who controls the light controls the first impression. The first impression is where the price gets set.

So, the rule. I do not judge color in the seller’s light. Ever. It costs nothing to carry the light with you, and it changes the conversation the moment the torch comes out. The serious sellers nod. They would do the same at my table.

The torch settles arguments about light. The master stones settle arguments about memory. Color memory is a myth, mine included. A ruby held beside a graded master tells the truth in about four seconds. A ruby judged against the ruby you remember from last month tells you a story, and stories are expensive.

Poor light also hides windows. Tilt the stone slowly through the beam and watch the return. A well-cut ruby holds its color as it moves. A windowed one goes glassy in the middle, and a warm lamp fills that hole with borrowed fire. Daylight leaves it empty, which is what your client will see at lunch.

When I can, I walk outside. Northern daylight at midday remains the reference standard of the entire colored stone trade, and it is free. In a market town nobody is surprised. In a Bangkok office tower it raises eyebrows, and I go anyway. The elevator ride has saved me more money than any instrument I own.

Buy the stone you saw in your own light. If it needs the back room to look right, you have learned something important about the stone, and about the room.