How do crystals work? - Graham Baird

Summary

The video delves into the fascinating process of crystal formation, exploring how magma beneath Yellowstone’s hot springs crystallizes into minerals like quartz and galena. It explains how atoms are organized into repeating patterns, which dictate the shape of crystals, from cubes to hexagonal columns. Environmental factors such as pressure, temperature, and chemical composition influence the shape and growth of crystals, with diamonds serving as a prime example. The video also touches on the practical applications of crystal properties in fields like materials science and medicine, showcasing how understanding crystals can drive scientific innovation.

Takeaways

• 😀 Crystals form as magma cools and solidifies, with minerals like quartz, feldspar, and galena emerging from the process.
• 😀 Groundwater carries minerals to the surface, where cooling causes ions to precipitate out and form crystals.
• 😀 Crystals grow in highly organized, repeating atomic patterns, which result in specific geometric shapes.
• 😀 There are six main crystal families based on atomic arrangements: cubic, tetragonal, orthorhombic, monoclinic, triclinic, and hexagonal.
• 😀 Galena forms cubic crystals where lead atoms create a 90-degree grid with sulfur atoms fitting between them.
• 😀 Quartz forms hexagonal crystals, which consist of interlocking pyramids made of silicon and oxygen atoms.
• 😀 Diamond crystals also have a cubic structure but can grow into different shapes like cubes or octahedrons, depending on temperature and pressure.
• 😀 Diamonds typically form cubes at lower temperatures and octahedrons at higher temperatures, influenced by environmental conditions.
• 😀 Glass, although made from quartz, does not form crystals because its atoms cool too quickly to form a structured pattern.
• 😀 The growth of crystals can be inhibited when multiple crystals grow in close proximity, as seen in rocks like granite, where shapes are not visible.
• 😀 Crystals have powerful applications in materials science and medicine, due to their unique atomic properties.

Q & A

What causes the crystals in Yellowstone's hot springs and geysers to grow into distinctive shapes?

The crystals form distinctive shapes due to the arrangement of their atoms in a highly organized, repeating pattern. This atomic structure influences the final shape of the crystals as they grow.

What types of minerals are formed in Yellowstone's hot springs and geysers?

Minerals such as quartz (from silicon and oxygen), feldspar (from potassium, aluminum, silicon, and oxygen), and galena (from lead and sulfur) are formed as the water cools and minerals crystallize out.

What are the six crystal families based on atomic arrangement?

The six crystal families are cubic, tetragonal, orthorhombic, monoclinic, triclinic, and hexagonal. These families categorize crystals based on the arrangement of their atoms.

How do environmental conditions affect the shape of crystals?

Environmental factors such as pressure, temperature, and chemical environment influence the shape of crystals. For example, diamonds can form as cubes or octahedrons depending on temperature conditions.

Why do diamonds grow into cubes at lower temperatures and octahedrons at higher temperatures?

Laboratory experiments suggest that diamonds tend to form as cubes at lower temperatures and as octahedrons at higher temperatures due to the conditions that influence their atomic arrangement.

Why don't diamonds naturally grow into the shapes seen in jewelry?

Diamonds found in nature do not naturally grow into the shapes seen in jewelry, as those diamonds have been cut and polished by humans to enhance their sparkle and clarity.

Why is glass not crystalline, despite being made from quartz sand?

Glass is made from melted quartz sand, but it cools too quickly for the atoms to arrange themselves into a crystalline structure. The atoms in glass remain randomly arranged, resulting in an amorphous (non-crystalline) material.

Why don't some crystals form recognizable shapes?

Some crystals do not form recognizable shapes because they grow in very tight spaces, such as within rocks like granite, where there isn't enough room for individual crystals to develop distinct forms.

Why doesn't turquoise grow into a geometric shape in most environmental conditions?

Turquoise typically does not grow into a discernible geometric shape because its atomic structure and environmental conditions do not support the formation of regular, well-defined crystal shapes.

What are some practical applications of the unique properties of crystals?

Crystals have powerful applications in materials science and medicine due to their unique atomic structures. These properties enable them to be used in various technological and therapeutic fields, though they may not directly impact human emotional needs.