สอบถามสินค้าและบริการได้ทุกช่องทาง This is simply not to say that softer stones, like serpentine, cannot be polished, but they must only be polished with other stones of similar hardness and not blended with more challenging stones. This is often achieved by the continual friction amongst the rock along with the polishing medium, https://beediadiamond.com/catalog/polishing-stones