Quasicrystalline Products

CONCLUSIONS

In a survey, prior to 2021, of which around 1,500 US consumers responded with their response to the question “What comes to your mind when you think about lab-grown diamonds?”, the terms “Artificial” and “Fake” were the most prevalent (8) . When you compare this image to that around real diamonds, which are associated with glamour and romance, it is difficult to imagine that lab-grown diamonds will survive and expand in the luxury market and be sold by top brands. However, unlike real diamonds which need to be mined, diamonds grown in labs provide an ethically sourced alternative which are typically sold at two thirds the price. With continued improvements in the HTHP and CVD technologies, these prices can be expected to drop further. This opens up synthetic diamonds to a wider market of luxury goods consumers who are more price sensitive. They can also appeal to consumers who opt for products that cause less damage to the environment and raise less concerns over human rights issues. From a regulatory perspective, the US Federal Trade Commissions expanded its definition of a diamond in 2018 to include lab-grown stones which could further stimulate their increase in sales (9) .

The industrial applications of diamonds also continue to grow. Recently, diamonds have found application in the rapidly expanding field of quantum computing. Unlike natural diamonds, lab grown diamonds will be able to support this industry due to their fast growth time and cheaper prices.

The diamond industry has many facets. It is clear that lab grown diamonds will be essential for existing and new industrial applications that require the unique features of diamonds. In contrast, the extent of entry of synthetic diamonds into the luxury goods market will depend more on social trends related to economics, sustainability and ethical considerations.

-Nadia

How can an understanding of the composition of quasicrystals instigate the reinstatement of quasicrystalline products?

What is a quasicrystal?

A quasicrystal is an aperiodic crystal whose structure both displays the precision of a crystal lattice as well as amorphous characteristics, in which its pattern is more subtle and nonrepeating. (1)

The discovery of quasicrystals Before the discovery of quasicrystalline solids in 1984, there were only two known forms of solids: crystalline and amorphous solids.(2) Quasicrystals were allegedly discovered, through the use of an advanced electron microscope, by Dan Shechtman (researcher from the Israel Institute of Technology), after the process of mixing aluminium with manganese in an

approximately six-to-one proportion caused a pericyclic reaction and resulted in an alloy of five-fold symmetry (symmetry forbidden in crystallography and quasiperiodicity ) (3) This process involved the rapid cooling of this molten manganese and aluminium alloy through ‘melt spinning’. This discovery was such a phenomenon that it gave rise to a lot of controversial thoughts and scepticism, even leading to Schechtman being dismissed from the lab by his boss who initially doubted his findings. (2) But what Shechtman’s boss didn’t know was that Shechman himself would go on to win the 2011 Nobel Prize in chemistry for his incredible discovery.

Icosahedral quasicrystals Icosahedral quasicrystals were the first reported quasicrystal. They exhibit long range order, meaning both symmetry and the regularity of particle arrangement are present within the structure, however unlike regular crystals, there is a lack of translational periodicity. This is implied by the fivefold symmetry which can be identified using electron diffraction, allowing the ten concentric rings of spots (indicating the axes) to be seen. (4) The reasoning behind why there is an irregularity in periodicity is simply due to the idea that pentagons placed side by side will not fill the space like a sequence of squares would. This was demonstrated by Pat Theil’s (scientist at the US Energy Departments Ames Laboratory) bathroom tiling analogy. Therefore, additional atomic shapes are naturally added to fill in the gaps. (5)

The reintroduction of quasicrystals Quasicrystals have been proven to have many favourable qualities such as being light absorbing as well as possessing beneficial electrical properties. However, suspicions were raised when miniscule cracks within the quasicrystals called ‘grain boundaries’ were discovered. These cracks resulted in the quasicrystals becoming more susceptible to risks such as the onset of corrosion, making them ineffective substances for domestic use. Despite this set-back, it was later