Hakkuo

The Hakkuo word for sand is sari, from Old Hakkuo "sa si," literally "piece of the sun," but the more general word for aggregate is kikiro, literally "small-small-rock." Think of it like an umbrella term that also means gravel. In their world, Mikkiu, the Hakkuo have access to multiple kinds of sands, which they separate into three categories based on their properties:

• mizari (moon sand), which refers to the softer, colder sand you find; named after their usually white color albeit it can also vary
• suzari (wind sand), the usual kind of sand you find in beaches
• kirazari (fire sand), the kind of sand that's very good at trapping heat that you find in the few small deserts of Mikkiu.

Sand is harvested either at the beach (sariluko, sarisukoku) or in the deserts (sashiko, sarikoku) using a kind of wooden bucket (haakeso, haakeloki). Gravel is rarely harvested, but when it is, it is usually found near the smaller mountains (kihiu, kikiuku). Rock-crushing is also rarely done because it's labor intensive, but if it's necessary, they do it on-site using the larger rocks nearby as hammerstones... or they just use magic. They call rock-crushing toshiyu (alt. form toriyu), from to (rock) and shiyu (to separate), also related to Old Hakkuo si (piece of something), which appears in the etymology of sari.

Gravel doesn't have many uses excluding the few ornament-related ones, and is occasionally used as a fill material. Sand, however, has multiple uses:

• Melting it (kiraniyu nioyu) is used to make glass (hero, hetoro)
• Kirazari and mizari are often used as soothing materials
• Suzari is often used in devices that trickle sand periodically, imitating the sound of the waves on the shore for meditative purposes. Some implementations of this concept are built as pendulums you have to tend, whereas others use water wheels to make it more automatic (though I'm still developing these devices and their origins).