1. Look at the selection of materials: For crystal products with well-selected materials, there should be no gas-liquid inclusions distributed in the form of stars, bulutlar va to'dalar. Tekstura toza, porloq, va kristal tiniq. Turli xil chuqurlikdagi yoriqlar va dog'lar bo'lsa, bu nuqsonli mahsulotdir. 2. Regarding workmanship: There [...]
