Sandalwood is generally harder than elm wood. This conclusion is based on the Janka hardness scale, which measures the resistance of wood to indentation. Sandalwood typically has a Janka hardness of around 2,000 pounds per square inch (psi), while elm wood ranges from 1,330 to 1,460 psi. This indicates that sandalwood is significantly more resistant to indentation and wear, making it harder than elm wood.

The hardness of wood is influenced by its cellular structure, specifically the density and arrangement of its fibers. Sandalwood, belonging to the genus Santalum, has a fine, tight grain and high oil content, which contribute to its hardness. Elm wood, on the other hand, has a coarse grain and lower oil content, making it softer and more susceptible to dents and scratches. These differences in cellular structure and composition result in the higher hardness of sandalwood compared to elm wood.