What does opaque mean in earth science?

opaque materials do not allow light to pass through them. These materials are composed of minerals, such as sand, stone, or clay. They are very common in the ground and are valuable in the creation of natural resources like sand and gravel.

What does it mean in earth science to be opaque?

If the mineral is relatively dark, such as iron oxide, it is opaque. Opaque minerals reflect back most or all of the light that strikes them. When they are highly crystalline, they are called glass. If the mineral is a liquid, it’s called lava. If a large chunk of molten stone, called magma, cools slowly to form a rock, it becomes crystalline, but the resulting crystalline structure can be opaque.

What does opaque mean in term of earth science?

Most of the minerals on the earth’s surface are either crystalline (lattice structure) or glassy. While some minerals are partly crystalline and partly glassy, others are entirely one or the other. The term opaque minerals refers to those that are entirely crystalline. So, minerals that are partly crystalline and partly glassy are not opaque.

What does it mean to be translucent in earth science?

Common earth materials that are translucent include sand, silica, and clay. Translucent materials allow visible light to pass through them, although not in a uniform way. Translucent materials can be described mathematically as having an index of refraction of between 1.0 and 2.0, meaning that they reflect light more as an interface between two different mediums than as a solid. Translucent materials have an effective density closer to that of air than to water, which is why they float.

What does opaque mean in geology?

In geology, an opaque rock is one that does not allow light to pass through it. In other words, it does not allow minerals to scatter or refract light the way a clear crystal does. This type of rock is usually created by pressure. Silica, or sand, is one of the easiest minerals to combine into a glassy, crystalline mass under extremely high pressure. Other minerals, such as quartz or volcanic ash, can also form opaque rocks when compacted to high pressure and