Opal stone is a relatively soft, milky-light-green (although sometimes with a brown undertone) serpentine with a fine, smooth texture and near translucent surface. It is often specked with red, orange or blue and the overall appearance can be smooth or mottled.
Opal stone is popular with sculptors, as it’s not as hard as springstone but still polishes to a high finish- revealing rich colour and beautiful texture.
Rating on Mohs hardness scale (with 1 being as soft as talc and 10 being as hard as diamond): 5.0-5.5.
Springstone is one of the hardest of the shona stones, which, along with its softer brown outer layer, make it very popular with sculptors. Although found in several areas, springstone is mined in Guruve, by hand. It is a dark stone and, due to its density, can be polished up to a high shine.
The dark colour of the stone can make for a great contrast when displayed in a light environment, and gives pieces of this material a great weight and presence. Rating on Mohs hardness scale: 5.5.
Cobalt stone can be purple or green, with either yellow and white or brown/orange markings. It is brittle and relatively rare making it quite a challenging stone to work with.
For those sculptors who have the skill however, the bright colour and variety of texture can allow for the production of some stunning works. Rating on Mohs hardness scale: 5 – 6
Dolomite is a relatively soft stone, which is often white – pink. When iron is present in the material, it can also be yellow, gray or even black. Dolomite is a common stone, mined in many places and is not exclusive to shona sculpture. However, its ease of carving and availability make it a popular choice. It is also often found with transparent white crystals in its structure. When polished, this helps give a pearly, shiny luster.
Shona artists who work in dolomite often produce larger works, thanks to the ease of working and the relatively low cost due to its availability. The crystals within its structure can add depth and even some sparkle to a work in the right light. Rating on Mohs hardness scale: 3.5 – 4
This stone is found across the world, and in a great many deposits within Zimbabwe. There is a large variation of colour and hardness within Serpentine, and as such it is a very versatile material. It can range from black-brown to green and even orange in some instances. Due to the natural variation in hardness, artists are able select a stone with properties that suit their needs and intentions. Often harder serpentine is used to allow for a more durable piece. There are some variations of Serpentine known as “Fruit serpentine” which are particularly colourful and varied deposits, often with deep veins of variated colours. When polished, the lustre is dependent on the type of stone and can again vary greatly. Rating on Mohs hardness scale: 1.2 – 6.5
As the name suggests, Butter jade is a yellow, creamy shade – and is lined with darker strata throughout. However, it is not nearly as soft as butter- being quite a hard, durable stone. Despite the name, it is not a true Jade but carries the name due to similarities in finish and hardness. Butter jade is common to South Africa, but is rarely found elsewhere- the stone was formed 50 million years ago, and was given its characteristic darker streaks and lines due to layers of fossilised algae as the rock was forming.
The unusual colouration and pattern of this rock makes it a desirable material to sculpt from, as the natural variation within it adds beauty and complexity to any design. Hidden colours and patterns within the rock are revealed to the artist as they work, providing surprises as the form is slowly revealed during sculpting. Rating on Mohs hardness scale: 6 -7
Sapolite is a hard, white stone which is sometimes misleadingly called “White Opal”. However, it is very different from the gemstone. It is not often used by sculptors, perhaps owing to its hardness and the fact it is mined only in one area. Sapolite gives a pleasing white, waxy colour with a slightly pearly luster. Unusually, Sapolite is rarely finished or polished with a wax- as once waxed, sapolite will turn a creamy brown with pink tints. Generally this change in colour is considered undesirable, as it loses some of the natural features and colour of the stone in the process.
Lemon Opal is a type of opal stone, differentiated from the usual greenish hue of opalstone by it’s yellow striations within the stone. These are caused by veins of quartz, and are what give it its namesake, giving a lemony textured hue to the stone. This quartz also provides a greater depth of colour to the greens within the stone, giving an overall more colourful material. Typically, it is harder to sculpt that standard Opal stone and is also rarer, being found in fewer places. When finished, it gives a deep yellow-green, textured look with pleasing variation and a bright luster
This is a creamy yellow coloured stone, with scattered black spock marks similar to those of a leopard. Leopard stone is a variation of serpentine. It is run through with iron rich minerals that form marks that look similar to leopard spots. This provides the namesake of the stone. Often, leopard rock will also contain bands of petrified wood, which also contributes to the pattern and feature of the rock. Unlike serpentine, it is a very hard stone and is typically very difficult to work with and to get the best out of. Typically, only skilled sculptors will attempt to carve using this rock. In addition, it is only mined in one area, meaning that Shona work using this material is relatively rare.