5: Semi-precious stones

All precious and semi-precious stones are commonly called gemstones or an equivalent name in several countries. Famous semi-precious stones include the red carnelian, pink rose quartz, lustrous gold pyrite, and turquoise, in the colour of the same name. Finland is known for its semi-precious rainbow-coloured spectrolite, found in Ylämaa in the South Karelia region.

Malachite

Malachite occurs in many places around the world. Old deposits in Egypt were depleted thousands of years ago, as were the Uralian deposits in the last millennium. Most malachite is now mined in the Republic of the Congo. Smaller amounts have been found in the United States, France, Mexico and Australia.

Prehnite

Prehnite usually occurs in volcanic rock cavities. It was first discovered in the 18th century by the Dutch Colonel Von Prehn, after whom the stone was named. Prehnite was considered rare at first, but new deposits were later found in various locations, including Morocco, Australia and Canada.

Kyanite

Some kyanite crystals, particularly the polished ones, often display the cat’s eye effect, a banded reflection that moves depending on the angle it is viewed from. Kyanite occurs rather widely. Some known Finnish deposits reside in Koli, North Karelia, and several locations in Northern Finland.

Turquoise

Turquoise was mined in Egypt at least 3,000, maybe even 4,000 years ago. South American Aztecs also used it in striking decorative art objects from the 14th to the 16th century. Turquoise has been found in China, Chile, the United States and Mexico, among other places.

Jade

The longest tradition in sculpting with jade is in China, where it has been practised since around the 3rd century BCE. Emerald-green jade is the most valuable variety. Jade is generally opaque or only slightly translucent. Nephrite has been found in the Helsinki capital region in Finland.

Lapis lazuli

Lapis lazuli, or lapis for short, is a deep violet blue stone whose best-known deposits are in northeastern Afghanistan. The world’s most cherished, very vivid-coloured lapis lazuli comes from there. The blue colour is caused by lazurite, but lapis also contains shiny golden pyrite and often smaller amounts of white calcite.

In Europe from the 16th to the 19th century, lapis lazuli was regularly ground into fine pigment, ultramarine, very valued in painting. It remains the world’s most expensive known pigment. The upper-class Ancient Egyptians used lapis powder as eye make-up. Even the mask of Pharaoh Tutankhamun from the 14th century BCE contains lapis lazuli.