The property that most easily distinguishes sulfur from other solid substances is its bright yellow color.

Here's why:

* Sulfur is the only common solid element with a bright yellow color. Most other solids, like metals, are gray or silver, while non-metals like carbon (coal) are black.

* Other properties of sulfur, like its odor or its ability to burn, might be harder to observe or less distinctive. For example, many substances have a smell, and some can be burned.

Therefore, the bright yellow color is the most easily recognizable and unique characteristic of sulfur.