Gemstones in the Universe

Before delving into extraterrestrial gemstones, it's essential to understand the formation of gemstones on Earth. Most gemstones are minerals formed under high pressure and temperature conditions within the Earth's crust. Diamonds, for instance, are formed in the mantle and brought to the surface through volcanic eruptions. These precious stones not only serve aesthetic purposes but also provide insights into the geological processes of our planet.

Most gemstones form deep within the Earth's crust or mantle under extreme pressure and temperature conditions. These conditions facilitate the growth of crystal structures that define gemstones. For example, diamonds form about 150-200 kilometres beneath the Earth's surface and are brought to the surface by volcanic eruptions.

There are over 200 recognized varieties of natural gemstones. These can be broadly categorized into precious stones, like diamonds, rubies, sapphires, and emeralds, and semi-precious stones like amethyst, opal, turquoise, and garnet. Each type has distinct characteristics and formation processes. While diamonds are made of carbon, rubies and sapphires are forms of corundum, an aluminum oxide mineral.

The formation and location of many gemstones provide clues about the Earth's tectonic activities. The creation of Himalayan gemstones like sapphires is linked to the collision between the Indian and Eurasian tectonic plates.

HAT-P-7b, an exoplanet approximately 1,040 light-years away in the constellation Cygnus, offers a unique window into the potential for gemstone formation beyond our solar system. This gas giant, discovered in 2008, has been the subject of extensive study due to its distinct characteristics, which suggest the possibility of exotic gemstone formation.

HAT-P-7b is classified as a "hot Jupiter," a gas giant that orbits very close to its star. It is significantly larger than Jupiter in our solar system, with a radius about 1.4 times that of Jupiter and a mass around 1.8 times greater. HAT-P-7b experiences intense heating from its star, with estimated temperatures reaching 1,900 degrees Celsius (3,500 degrees Fahrenheit). These high temperatures contribute to a dynamic and possibly turbulent atmosphere.

The extreme temperatures and possible presence of mineral clouds in HAT-P-7b's atmosphere provide a theoretical basis for the formation of gemstones. Scientists have speculated that the conditions could lead to the formation of corundum, the mineral responsible for rubies and sapphires on Earth.

The sapphires - and rubies - on this planet differ vastly from those on Earth, manifesting not as solid gems but as powerful gusts of wind carrying sapphires and rubies throughout the atmosphere. Studies indicate that the planet's clouds might consist of vaporized corundum. These findings suggest that intense winds traverse the planet, moving clouds from its night side to its day side. These winds vary significantly in speed, causing massive cloud formations to accumulate during night time and then dissipate rapidly daytime.

However, it is essential to note that the idea of gemstone formation on HAT-P-7b is based on theoretical models and spectroscopic observations. Direct evidence of such gemstones has not been obtained, but the study of exoplanet atmospheres and compositions continues to advance, offering hope for future discoveries.

The Moon, Earth's closest celestial neighbour, holds potential for gemstone discoveries. The recent discovery of spinels within traces of anorthosite on the moon has added a fascinating chapter to our understanding of lunar geology. Anorthosite, a rock composed largely of plagioclase feldspar, is predominant in the lunar highlands. The presence of anorthosite on the moon's surface has long been understood to be a relic of the early lunar crust, formed as lighter minerals floated to the surface of a global magma ocean that enveloped the young moon.

The finding of spinels, which are minerals typically rich in magnesium and iron, within these anorthosite traces is particularly intriguing. Spinels are formed under high-pressure conditions, which suggests a complex geologic history involving significant pressures beneath the lunar surface. This discovery challenges the traditional models of the moon's formation and early development, indicating a more dynamic internal process than previously thought.

The spinels' presence in lunar anorthosites points to a period in the moon's history where the interior was hot and active, allowing for the crystallization of these minerals under high pressures. This scenario proposes that the early moon experienced intense geological activity, forming these minerals deep beneath the surface. Eventually, these spinels were brought to the surface, embedded within the anorthosite, possibly through tectonic activity or asteroid impacts.

This finding also has implications for our understanding of the lunar interior. The composition and distribution of minerals like spinels can offer insights into the thermal and chemical processes that have shaped the moon. By studying these minerals, scientists can glean information about the depth and extent of the early magma ocean, the moon's thermal history, and the processes that have driven its geological evolution. It also provides a valuable comparison for understanding planetary formation and crustal evolution on other celestial bodies. This contributes to a broader understanding of planetary geology, extending beyond our moon to other planets and moons in our solar system and beyond.

In the vast expanse of our galaxy, there exists a phenomenon as enchanting as it is scientifically intriguing: the occurrence of diamond rains on certain planets. This impressive process, transcending the realms of science fiction, is a reality in the atmospheres of some gas giants, akin to Neptune and Uranus in our own solar system.

The formation of diamond rain is a result of the unique atmospheric conditions and chemical compositions found in certain gas giants. These planets possess atmospheres rich in hydrogen and carbon, the fundamental building blocks of diamonds. The process begins deep within the planet's atmosphere, where extreme pressure and temperature conditions exist.

In these lower layers of the atmosphere, the intense pressure – which can be millions of times greater than that on Earth – and high temperatures cause methane gas (composed of carbon and hydrogen) to decompose. This decomposition separates the hydrogen and carbon atoms. The carbon atoms are squeezed under immense pressure and transformed into diamond crystals.

Once formed, these diamond crystals do not remain suspended in the atmosphere. Due to their density, they begin a slow descent towards the planet's core. During this journey, the diamonds experience further pressure and temperature changes. It is speculated that, on some planets, these diamonds might melt into a liquid form due to the extreme heat as they approach the core, creating 'diamond oceans'.

Understanding the universe through the study of gemstones is a fascinating aspect of both geology and astronomy. Gemstones, whether found on Earth or theorized to exist on distant planets, provide a unique lens through which we can examine the formation and evolution of celestial bodies.

On Earth, the formation of gemstones offers valuable insights into the geological processes that have shaped our planet over billions of years. Each gemstone tells a story about the conditions under which it was formed.

Extending this concept to a cosmic scale, the potential discovery of gemstones on other planets, like the speculated corundum on HAT-P-7b, opens up a new realm of understanding. If such gemstones exist on other planets, they can tell us about the atmospheric composition, internal processes, and even the history of these distant worlds. Finding diamonds on a planet would suggest a carbon-rich environment and extreme internal pressures, providing clues about the planet's formation and evolution.

Moreover, studying gemstones in the universe context helps understand the diversity of planetary systems. It challenges our Earth-centric view of mineral formation and expands our knowledge of the types of environments that exist in the cosmos. This understanding can also contribute to our search for extraterrestrial life by identifying planets with conditions similar to Earth or entirely new environments where life could potentially exist.

Gemstones are not just beautiful objects to be admired but are also scientific tools that can help unravel the mysteries of the cosmos. By studying gemstones, we gain a deeper appreciation of the complexity and diversity of the universe and our place within it.