This rock may occur as below the Earth's surface as in space, too. For centuries humanity was tricked into thinking it was a precious mineral.
Egyptian people were aware of olivine deposits as far back as several thousand years ago. As legends say, Cleopatra herself was particularly fond of jewels with this mineral. At that time it was believed olivines fell down from the sky, hence they were called 'sunstones'. Priests of ancient Egypt powdered the mineral to add it into drinks, in strive for spiritual enlightenment.
The Roman Emperor Nero used an olivine crystal to restore his vision. Doctors suggested the ruler gaze at green-coloured objects to cure short-sightedness. Following the prescriptions, Nero wore clothes of the 'right colours' only. He ordered his private rooms to be decorated with stones of respective colours and the arena gladiator fights took place at to be dusted with ground malachite. The Emperor also had an olivine rock he used as a monocle. Seeing through it, the Emperor enjoyed watching the slaughterous games and even the scene of burning Rome. As it turned out later, the rock he thought was the emerald and called the 'Emerald of Nero' had nothing to do with the gemstone.
Olivine had been long mistaken for emerald, which is explained by their relatively similar outward appearance. Ancient Romans already knew of a rare optical property of olivine. Upon darkness setting in, the stone's colour was changing from yellow-green to a saturated shade of green. Because of that feature, the mineral got the name 'evening emerald'.
Olivine's colour depends on the concentration of impurities in a sample. It may vary from all shades of green to black or even transparent, with the colour being most clearly visible in artificial light.
The play of the light is what attracted Europeans to chrysolite, a gemstone variety of olivine. In the 19th century, jewels with this stone were very trendy. Ruling dynasties of many countries had items made of the mineral in their possession. Some notable examples are Fabergé eggs, ultra-pure piece of chrysolite reaching almost 193 carats in size, part of the Russian Crown's regalia joined with thirty diamonds, and the Queen of Norway's tiara.
Back in the olden days, there was a belief the mineral was sent from up above. It turned out it was not untrue at all. In the mid-18th century, an accidental discovery took place in Krasnodar Krai, when a first-ever Russian meteorite of about 700 kgs in weight was found. The first pallasite meteorite, which is composed of native iron and large olivine crystals, is commonly known as 'Pallas Iron'.
Three centuries afterwards, Japanese scientists, while studying remote sensing data from the Moon, discovered olivine deposits inside the craters of the celestial body. It is noteworthy that the mineral is also a primary component of the Earth's upper mantle. Therefore an assumption on the origin of the Moon, which was supported by many astronomers, is now confirmed. According to the hypotheses, it was formed through a collision of the Earth and a large body.
Since the mineral mostly originates from the lower layers of the mantle, it is often found inside the chunks of solidified lava. These pieces are taken to the surface during a volcano eruption. Sometimes, when a volcano collapses, olivine particles may be brought by the surf to the shore, and by blending in with sand, turn beaches green. There are several places in the world wherein the phenomenon may be observed, with one of them being in Hawaii. The Kīlauea volcano last erupted in 2018. Shortly after, people started finding small green stones with which all surrounding streets were covered. To the disappointment of local inhabitants, stone pieces were not of gem-quality. Still, they changed the way local landscapes look, thereby causing a surge in tourist activity.
Olivine is of interest to jewellers because of its noble lustre, vibrant colour, and ability to refract light. Specimens of the highest value are those that turn their colour from gold-green to greenish-brown. One of the world's finest and largest olivine rocks - a cut 311-carat sample - was found on Zabargad Island, Egypt, and is now on display at the Smithsonian Institution, the US.
