Buyers should prioritize K9 Crystal (Optical Borosilicate Glass), which offers superior clarity, a high refractive index, and minimal bubbles or streaks compared to ordinary glass. For the 3D internal structure, ensure the supplier uses Sub-surface Laser Engraving (SSLE) technology with a high point density to create detailed, non-opaque architectural features. If the model includes a base, verify if it is made of solid wood, zinc alloy, or integrated crystal to match the desired product positioning.