| Lighting | | | | Ruby was one of the first gems to be treated, |
| Proper lighting is crucial with any colored stone, | | | | with reports detailing the heat treatment in Sri |
| but it is particularly important with ruby. The | | | | Lanka dating back over 1000 years. But today's |
| culprit is the fluorescent tubes so much a part of | | | | treatments are far more sophisticated than the |
| the modern office. | | | | primitive heatings of years gone by. |
| Most fluorescent tubes are so red-deficient that | | | | Today, ruby heat treatments run the gamut. The |
| what they do to the color of a ruby should be | | | | simplest is heating to knock out the blue |
| outlawed. The reason is not hard to fathom. Ruby | | | | component that makes a stone purplish. Such |
| requires a light source with at least some red in it, | | | | heating can be done at lower temperatures (say |
| and fluorescent tubes ain't got none. Thus to bring | | | | 700-1200 °C) and is often undetectable. |
| out the inherent beauty in your stones, use | | | | Another type involves heating to higher |
| halogen or incandescent bulbs, or natural skylight. | | | | temperatures (1200-1800 °C) to remove |
| When using skylight (not direct sunlight) to view | | | | rutile silk, and this is generally detectable. |
| gems, keep in mind that red stones will appear | | | | But the type of heating that is most controversial |
| best around noon, while blue stones look their | | | | is that applied to Mang Hsu rubies. This involves |
| finest just after sunup and just before dusk. So | | | | heating (1200-1800 °C) in the presence of a |
| the rule is, if buying with natural light (skylight), | | | | flux. The flux produces healing of surface-reaching |
| don't buy rubies (or red spinels) in the middle of | | | | fractures and openings. Thus a highly fractured |
| the day. | | | | stone can be healed and the fractures dissipated. |
| Background checks | | | | A further treatment occasionally seen is oiling |
| A word should also be said about the viewing | | | | staining. Gentle heating in alcohol (be careful!) can |
| background. At mining areas in Burma and | | | | generally remove oils/stains. |
| elsewhere, rubies will often be sold on brass | | | | One of the true tragedies of gemstone |
| plates, yellow table tops or in stone papers with | | | | enhancements is that they raise expectations |
| yellow liners (flutes). This makes the purplish red | | | | among the gem-buying public to unreasonable |
| color more reddish. Place your stones on a white | | | | levels. Once a customer has seen the shocking |
| background for accurate color assessment. | | | | reds produced by human tampering, it becomes |
| Parcels | | | | far more difficult to accept the more ordinary |
| Buying parcels is a specialized area beyond the | | | | hues of nature. No where is this more true than |
| scope of this article, but I do want to mention | | | | with Maing Hsu ruby. |
| that parcels often look great with all the gems | | | | I will not go into enhancement ethics. But it is |
| piled together. This is because they draw color | | | | essential that both buyers and sellers are aware |
| from one another, with each gem adding color to | | | | of the presence of any treatment, for they can |
| the whole. For an accurate assessment of color, | | | | have an important impact on value. It is my |
| spread the parcel out such that individual gems do | | | | personal opinion that, when spending a significant |
| not influence the color of those nearby. | | | | sum of money on a ruby, one should avoid |
| Treatments | | | | treated stones of any kind. |