Although the words 'mineral', 'stone', 'crystal' and 'gemstone' are often used interchangeably, they actually imply different structural properties.
STONE (ROCK)
Stone or rock consists of a fixed combination of different minerals and does not have the specific chemical composition that you normally find in a mineral.
So a stone always contains several minerals and has a natural origin.
Three examples of rocks are:
• Lapis Lazuli: This consists of lazurite, calcite and pyrite.
• Jade: It consists of two different minerals: jadeite and nephrite.
• Tiger's Eye: It consists of quartz with inclusions of fibers of the mineral crocidolite.
MINERAL
A mineral is a natural substance that occurs in the earth's crust and consists of one specific chemical element or a composite chemical compound. It has a solid crystal structure and can occur in different shapes, colors and hardnesses. They are formed by geological processes, such as crystallization from molten rock, deposition from aqueous solutions, or biological precipitation. Although not all minerals are crystals visible to the naked eye, they do contain microscopic crystals.
There are a number of important characteristics that define a substance as a mineral: it must occur in nature, contain no organic substances, be in a solid state at room temperature, have a clear chemical composition and have an ordered internal structure.
Minerals form the basis of rocks and come in different shapes and colors.
5 well-known examples of minerals are:
• Hematite
• Pyrite
• Opal
• Quartz (mineral with a crystal structure)
• Amethyst (mineral with a crystal structure)
CRYSTAL
Most minerals occur in nature as crystals.
A crystal is a solid whose atoms, molecules, or ions are arranged in a regular and repeating manner in space, resulting in a crystal lattice. So the atoms are spaced at very precise distances and angles from each other to form a crystal.
This creates specific characteristics such as flat and smooth surfaces, angular shapes and refraction of light.
Crystals come in different shapes and sizes and can be formed by both natural and synthetic processes.
The crystal structure can influence the physical properties of a mineral, for example color, luster, texture and shape.
Popular crystals of one mineral are:
• Amethyst
• Rock crystal (clear quartz)
• Citrine
• Calcite
• Ruby.
• Emerald
GEMSTONE
A gemstone is a valuable mineral, crystal or rock that is cut and polished for use in jewelry and decorative items.
Gemstones are known for their beauty, clarity, color and rarity, and they have been valued for centuries for their aesthetic and symbolic value.
The most famous gemstones are diamond, sapphire, emerald and ruby.
But some new, modern gemstones are:
• Morganite
• Tanzanite
• Aquamarine
• Peridot
• Tourmaline