Snowflake obsidian after tumble polishing Rock polishing is a lapidary process whereby rough stone is polished and smoothed by hand or using simple machines to produce attractive stones. The most common means is tumble polishing, but there is also vibratory finishing . To effectively polish rocks in a tumbler the rocks must all be of the same approximate hardness. Rocks are placed into a tumbling barrel with varying degrees of abrasive grit and or water. Depending on the hardness of the rocks  each step in the tumbling process can take place over a number of days  . Rocks start out as something called a "tumbling rough", an untreated stone. A tumbling rough is placed into a tumbling barrel with abrasive grit and water. This initial procedure is called the coarse grind. The purpose of the coarse grind is to wear down any sharp or uneven edges on the rock's surface, eventually producing smooth round stones. The second stage of rock polishing is the fine grind. This  is the same as the coarse grind  differing only in the use of a finer grit  and that the stones are no longer shaped but are beginning to be polished. At the end of this step the rocks should appear shiny when wet, but matte when dry. The Pre-polish step uses a mixture of very fine grit and  plastic tumbling pellets. At the end of the process  the stones have a slight luster when dry. The final two steps are the polish and in some cases the burnishing. In the polishing step, rock polish is added in place of grit as well as the plastic tumbling pellets. After further tumbling  the rocks should now have a shiny look when dry. If this is not the case and the rocks appear to have a film on them, a burnishing  may be necessary. In burnishing  the rocks are tumbled with only the plastic pellets and the addition of an oil free non abrasive soap.
Snowflake obsidian after tumble polishing Rock polishing is a lapidary process whereby rough stone is polished and smoothed by hand or using simple machines to produce attractive stones. The most common means is tumble polishing, but a vibratory finishing process can be used instead . To effectively polish rocks in a tumbler the rocks must all be of the same approximate hardness. Rocks are placed into a tumbling barrel with varying degrees of abrasive grit and often with water. Depending on the hardness of the rocks , each step in the process can continue over a number of days of continuous operation of the tumbling barrel . Polished rocks start out as something called a "tumbling rough", an untreated stone. A tumbling rough is placed into a tumbling barrel with abrasive grit and water. This initial procedure is called the coarse grind. The purpose of the coarse grind is to wear down any sharp or uneven edges on the rock's surface, eventually producing smooth round stones. The second stage of rock polishing is the fine grind. This process is the same as the coarse grind , differing only in the use of a finer grit , and that the stones are no longer shaped but are beginning to be polished. At the end of this step the rocks would appear shiny when wet, but matte when dry. The pre-polish step uses a mixture of very fine grit and special plastic tumbling pellets. At the end of the process , the stones have a slight luster when dry. The final two steps are the polish and in some cases the burnishing. In the polishing step, rock polish is added in place of grit as well as the plastic tumbling pellets. After further tumbling , the rocks should now have a shiny look when dry. If this is not the case and the rocks appear to have a film on them, a burnishing step may be necessary. In burnishing , the rocks are tumbled with only the plastic pellets and the addition of an oil-free non-abrasive soap.
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there is also vibratory finishing
a vibratory finishing process can be used instead
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or
often with
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tumbling process can take place
process can continue
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of continuous operation of the tumbling barrel
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Rocks
Polished rocks
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process
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should
would
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Pre-polish
pre-polish
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special
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step
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oil free non abrasive
oil-free non-abrasive