In January 2021 workshop in the art of stone "Uraltash-art" LLC "Ural mining and geological Agency" (LLC "UMGA") were tested powders based on cerium oxide grades: "U", "M", "K", "DU", "D", "LM.1" produced by GC "Skygrad". As a source a hard stone "Kalkan jasper" was used, which is characterized by average polishability indicators among other hard stones. The preparation of the samples consisted in preparing the plates and grinding them with abrasive powders (in series: silicon carbide CF120, silicon carbide CF230, AGSHK «Cherepashka 800»). The polishing was carried out manually using a SNAYER POLYMAX polishing nozzle on felt.

The test results are shown in the table:

The conclusions of experts:

• LM powder is characterized by the lowest indicators.1. Its use is not recommended.

• Powders D, K and M are quite high-quality and can be used for polishing products made of natural stone.

• DU and U powders are a high-quality product for polishing high-hardness natural stone. DU-out of competition exceeds the quality indicators of imported analogues!