High-purity drugs usually have the following physical characteristics: 1. **Appearance**: - **Color**: High-purity drugs usually appear as white or almost white crystals or powder. For example, high-purity cocaine and methamphetamine (ice) are usually white crystalline powders. - **Texture**: The powder is fine and uniform, the crystals are regular, and there are no obvious impurities, color spots or uneven particles. 2. **Crystal morphology**: - **Crystal shape**: The crystal morphology of high-purity drugs is relatively regular, the crystal size is consistent, and the structure is clearly visible. - **Transparency**: The crystals are usually relatively transparent or translucent, lacking turbidity or turbidity. 3. **Smell**: - **Pure smell**: Due to the high purity, the smell of drugs is usually more single and pure, and there are fewer adulterants, resulting in less odor. 4. **Melting point**: - **Clear melting point**: High-purity drugs have a specific and clear melting point range. By measuring the melting point, its purity can be preliminarily judged. The higher the purity, the narrower the melting point range and the closer it is to the theoretical value. 5. **Solubility**: - **Consistent solubility characteristics**: High-purity drugs have consistent solubility in specific solvents, and no abnormal precipitation or suspended matter appears, indicating that there are fewer adulterants. 6. **Crystallization water content** (for certain drugs): - **Hydration state**: Certain high-purity drugs may present a specific hydrated crystal form with a stable hydrated water content. It should be noted that different types of drugs may have different purity characteristics, and the above characteristics mainly apply to common high-purity white powder drugs. In addition, the appearance and physical properties of illegal drugs may vary due to different production processes and adulterants. The above description is for reference only.