On the other hand, sandstone, which is formed by individual sand grains compacting together, generally has a high degree of porosity. Specific Gravity refers to how much something weighs in comparison to an equal volume of water. Streak refers to the color that a mineral gives off when it is in powered form. The streak is usually determined by scraping a mineral along a ceramic white plate, known as a 'streak plate'. The streak is considered a much better method of identification of minerals than color.
Texture refers to the size, shape, and distribution of particles that make up a rock.
Transparency refers to the degree that light can pass through a mineral. If a mineral is opaque, light cannot pass through. If it is translucent, light can pass through, at least to some degree. When a volcano erupts, it forms igneous rocks. Examples of igneous rocks are gabbro, diorite, rhyolite, pumice, obsidian, granite, and andesite.