Volcanic ash and lapilli are two very common occurrences in a volcanic eruption. They occur when the molten rocks and lava are thrown in the air and cooled. Lapilli are bigger than as, as it can be as large as 64 mm, whereas ash is less than two mm at its largest. They are very common in volcanic eruptions, and are good clues towards finding where you are in a volcano.
Lapilli, meaning little stones in Latin, are somewhat large chunks of cooled lava. Normally, they look like shattered glass pieces , but sometimes they are melted together when a volcano has multiple eruptions. These are called welded tuffs. Bigger objects land closer to the volcano than smaller pieces, such as ash. Ash sometimes floats around the world in our atmosphere, because it is so small. Lapilli settle closer to the volcano, and the sections of lapilli get bigger. Ash, sometimes, mingles with the lapilli, forming layers that volcanologists use as timelines. They are very helpful in finding when the volcano erupted and for how long. Ash is very small, and tends to be everywhere. It coats many things in its reach like dust. Ash can also suffocate the residents of the volcano, becoming very dangerous. Ash and lapilli, however, are both pyroclastic flow, which also includes pumice, scoria, and many crystals. Pyroclastic flow are also known as tephra. Ash and lapilli also can form deposits when they gather. This is a good sign that you are close to the vent of a volcano.
Ash and Lapilli are very important pieces of volcanic eruptions. They can be found near volcanoes and used to find how long the eruptions lasted. They also can be used to see how old the volcano is. They are both very useful parts of the pyroclastic flow.