David Boyce and his students of Queenswood School in the UK are cultivating what they are terming as the largest single crystal of copper sulfate in the world. It presently weighs more than 2kg and has grown in a little more than a year.
How Crystals Form and Grow
When crystals begin to form molecules combine in a solution. Such small seeds dissolve and re-form until they are of a critical size, the size at which the total energy in the crystalline core matches the energy required to add molecules to the surface of the crystal. The process of growing crystals is a slow one, and it adds a layer of crystal structure to the previous one, temperature, concentration and impurities in the sample itself are all factors that influence the growth rate of the crystal.
Natural vs Artificial Giant Crystals
The natural crystals have occasionally had thousands of years to develop, and many of them are far larger than those of Boyce. What are some other world record-busting crystals, though?
Record-Breaking Giant Crystals
1. Copper sulfate
Although the crystal by Boyce is the largest single crystal of copper sulfate, the largest overall crystal is the one produced by students at the Kurfruest-Ruprecht-Gymnasium in Germany. Their polymorphic crystal was almost 70kg in weight and was given a Guinness World Record in 2010.
2. Gypsum
Under a mountain on Naica in Mexico lies the so-called cave of crystals containing extremely large crystals of gypsum or calcium sulfate dihydrate (CaSO₄·2H₂O). The milky-white crystals were found in 2000 by the mining company Industrias Peñoles and measure up to 11m long and weighing 4050 tonnes. Scientists believe that these would have grown in a period of approximately a million years.
3. Scheelite
The largest crystal of scheelite was created using calcium tungstate (CaWO₄): a 0.4m long, 0.3m high and 0.15m thick crystal is housed in Shandong Tianyu Natural History Museum in China.
4. Snow way!
In 2003, Kenneth Libbrecht took the largest snow crystal ever photographed in a light Ontario, in Canada. The snowflake is 10mm long, which is approximately half the diameter of a US cent coin. Larger snowflakes have been reported but these consist of separate snow crystals that have been clumped together — the largest cluster that has been observed was 38cm wide and 20cm thick.
5. Quartz
Silicon dioxide crystals or fine grains of these crystals covering beaches all over the globe are also referred to as quartz. However, in contrast to common sand crystals, a 14 tonne quartz crystal with a length and height of 3m apes the trophy of the largest quartz crystal on display in the world. They claim it took three years to be dug out of a mine in Namibia by miners.
6. The world’s biggest?
The beryl (beryllium aluminium silicate) crystal in Malakialina, Madagascar, weighing some 380 tonnes is an 18m long and 3.5m deep crystal and was one of the largest crystals ever discovered. Beryl crystals are precious gemstones but they are also a prime source of beryllium.
Honorable Mention — Crystal Structure Model
In 2015, crystallographer Robert Krickl created the largest model ever built of the lattice structure of sodium chloride with close to 40,000 plastic balls. Although it is not actually a crystal, the cube shape measures more than 3m long and incorporates an adequate number of connecting sticks so that, once joined together, they would have a length of more than 10km.
The ionic structure of the model is that of a crystal of salt 0.0000096mm in diameter. The crystal structure model by Krickl of sodium chloride can be observed in an interview with Agence France-Presse where his building was exhibited in Vienna.