The physical properties of high-purity drugs may vary depending on the type of drug, but here are some common characteristics: 1. Appearance: High-purity drugs often have a bright, uniform color and a fine texture. This is because unadulterated substances tend to have a more consistent crystal structure. 2. Crystal structure: Many high-purity drugs are in crystalline form, which may appear as needles, flakes, or cubes. These crystal structures are formed due to the regular arrangement of molecules. 3. Sheen: High-purity drugs may have a glassy or metallic sheen, especially when they are in crystalline form. 4. Density: High-purity substances tend to have a higher density than adulterated substances, which means they are heavier and less bulky. 5. Melting point: High-purity drugs often have a higher and more consistent melting point because the regular arrangement of molecules requires more energy to break. The melting point refers to the temperature at which a substance changes from a solid to a liquid. 6. Hardness: High-purity substances may be harder and more brittle than adulterated substances because the regular crystal structure makes them more resistant to mechanical stress. 7. **Solubility**: High-purity drugs may be less soluble in certain solvents, such as water or organic solvents. This is because the regular arrangement of the molecules makes it more difficult for the solvent molecules to penetrate the crystal lattice. 8. **Vapor Pressure**: High-purity substances generally have lower vapor pressures than adulterated substances, meaning they release less vapor. This is because the regular crystal structure makes it more difficult for the molecules to escape into the vapor phase. Some examples of the physical characteristics of specific high-purity drugs include: * High-purity cocaine: a white, crystalline solid with a smooth surface and needle-like or flake-like shapes. * High-purity heroin: a white, powdery solid with a smooth surface and high density. * High-purity methamphetamine: a white or yellow, crystalline solid with a glassy sheen and needle-like or cylindrical crystals. * High-purity ketamine: a white, crystalline solid with a smooth surface and cylindrical or flake-like crystals. Please note that these are general characteristics only and the physical appearance of a high-purity drug may vary depending on the specific substance, its production method, and the materials it may have been adulterated with.