The first layer of the earth’s crust, consists of about 10 miles of rock and loose materials. Underneath the continents, the crust is almost three times as thick as it is under the oceans. The ingredients used to make the Earth’s crust are complex.
The basic ingredients are known as elements. There are 90 known elements that exist in the Earth’s crust. These elements combine with one another in a number of natural ways, creating molecules known as minerals. There are around 3,700 known minerals found in the Earth’s crust, with dozens of new minerals being discovered each and every year.
Colour is the most eye-catching feature of many minerals. Some minerals will always have a similar colour, such as Gold, whereas some minerals, such as Quartz and Calcite, come in all colours. The presence and intensity of certain elements will determine a specific mineral’s colour.
Tumbled stones (also known as “polished stones” or “baroque gems” or “polished rocks”) are small pieces of rocks and minerals that have been rounded, smoothed, and polished in a rock tumbler. They are beautiful, colourful, brightly polished specimens of natural materials.
I’m not sure what all of mine are, it’s a long time since I collected them, but there is a large amethyst crystal, 2 x banded amethysts, snowflake obsidian, 2 x rose quartz, tigers eye, and 3 onyx eggs.