Polishing marble (from the flooring industry)

[NRG]

I think it applies to our use very well. Same material, marble/onyx/travertine.

From "The Slippery Stone Gazette"

The major complaint I receive is they can’t produce that deep factory polish – what some contractors refer to as a “ten foot shine.” These same contractors tell me they have tried less powder, more powder and all different types of marble polish, all to no avail. Some even complain of orange peeling.

And later

Powder Polishing Abrasives

What type of abrasives are marble and granite polishing powders made of? Most marble polishing powders use aluminum oxide as the abrasive, oxalic acid as the accelerator and a combination of other ingredients such as shellac, sulfur, salt, etc., which add color, lubrication, and so on, to the process. A “hot” powder is one which contains over 50% oxalic acid.

It is possible to blend your own polishing powders by mixing aluminum oxide and oxalic acid. I don’t recommend blending your own, unless you are experienced at doing so.

Caution: Oxalic acid, which is used to speed the polishing process, can burn marble. Burned marble has a characteristic dimpled appearance; the stone will have a molten, plastic shine. This burned appearance is commonly called “orange peel,” for reasons that are obvious to anyone who sees it. If you orange-peel the floor, you will have to re-hone the floor to remove it.

Any media called "The Slippery Stone Gazette" has my attention!

[NRG]

And a beautiful piece on polishing theory.

Why Does Stone Shine?

When stone becomes dull and scratched, it has obviously lost its factory shine and luster. At this time the stone needs to be refinished and polished to restore the shine it had originally. Why does stone shine, and how can a lost shine be recovered?

The deep shine we see on polished stone is achieved by rubbing the stone with a series of abrasive materials. The process is very similar to sanding a piece of wood. The stone is rubbed with a coarse abrasive grit, followed by finer and finer grits until the stone becomes smooth.

The scratches left behind from one grit are removed by the next, creating finer and finer scratches. The process continues until the scratches are microscopic.

The shine on the stone is achieved by abrading the surface to the point at which it becomes extremely smooth and starts to develop some reflectivity. The shine on the stone is thus, a product of optics.

In a rough or scratched piece of stone, when light is reflected from the stone, the light rays become scattered, producing a dull, flat appearance to our eyes. In a very smooth stone, the light is reflected on the surface and the light rays return in a parallel pattern, producing a deep reflective appearance.

This same optical property can be observed on a pond. When the wind is blowing and the surface of the pond is wavy, it becomes difficult to see a reflection; when the air is still and the pond is calm, a deep reflection can be observed. So, in order to achieve a deep shine on stone, all that really needs to be done is to smooth it until it shines.