Graywacke : A variety of sandstone generally characterized by its hardness, dark colour, and poorly sorted, angular grains of quartz, feldspar, and small rock fragments (lithic fragments) set in a compact, clay-fine matrix. Also spelled greywacke.
👇 ស្វែងរកឯកសាររៀននិងការងារគ្រប់ប្រភេទនៅទីនេះ៖
👇 ស្វែងរកពាក្យផ្សេងទៀតនៅប្រអប់នេះ៖