Medium hard formation with high compressive strength. Such as limestone, taconite, blaize, quartzite, silica sand, basalt, granite ect.

高抗压强度的硬地层，如硬石灰岩。燧岩。硬砂岩。石英岩。石英砂。玄武岩。花岗岩等极硬岩层。

youdao

Such beautiful landscape elements reflecting the locality of Jeju as stone wall, volcanic sand, and basalt rock were reinterpreted into the motif of this project.

如此美丽的景观元素，反映了济州岛的地方性，如石头墙，火山砂和玄武岩都转化为本项目的主题。

youdao

The sand is very probably just the product of weathered basalt, the ubiquitous volcanic rock on Mars' surface.

BBC: Nasa's Curiosity Mars rover to scoop sand sample