Contrary to popular belief, emeralds are very resistant to scratches. A direct measure of this is the Mohs Hardness Scale. Any mineral on the scale can be scratched by a mineral the same rank or above it, but cannot be scratched by anything below it.
While not directly listed on the scale, beryl has a hardness of 7.5-8 depending on the impurities in the crystal. It is more difficult to scratch than quartz and can be as hard as a topaz. Most things an emerald comes into contact with will not scratch it, which is why emeralds make for popular gemstones.
The highly included nature of emeralds has nothing to do with its hardness, and more to do with their durability (their resistance to being hit). In and of itself, beryl is very durable.
E1316 | medium | left | play | “Emerald ID: E1316 – Weight: 1.53 Carats – Origin: Ethiopia” The emerald variety of beryl is very included to the point of qualifying as a Type 3 gemstone . This makes them brittle and more susceptible to breaking when being hit. Bear in mind this is relative to other gemstones. Relative to an emerald, your finger will break before any emerald will. The process for cutting gemstones is brutal, and any gem that survives it is pretty tough.
Also bear in mind that nearly all emeralds are treated with oil to improve their clarity. E1316 on the left if visibly included. It has also been oiled, which means the inclusions are actually more visible.The inclusions are so prolific that the French refer to them as a “jardin” or garden.