Diamond Industry

Components for Synthetic Diamond Manufacture

Wonderstone Ltd is 100% owned by Assore Ltd. (listed on the JSE) and has been mining a uniquely pure Pyrophyllite deposit 300 kilometers west of Johannesburg, South Africa since 1937.  Wonderstone Ltd does not manufacture or sell synthetic diamonds, we do however manufacture various components from Wonderstone (Pyrophyllite), which have been used in the synthetic diamond industry for more than 60 years.   The remaining lifespan of the resource is estimated be another 70 years.

The mineral Pyrophyllite has played an integral role in the process of manufacturing synthetic diamonds ever since their discovery in 1954. Wonderstone has been the product of choice, because of its properties of thermal and electrical insulation and high compressive strength, while showing excellent gasket forming properties even under extreme operating conditions (>1,400 ºC, > 80 kbar).

Wonderstone is easily machined with standard machine tools and has the appropriate frictional and extrusion characteristics to form a gasket either between the die cavity and the two ramming punches in a belt die set or between the anvils in multi-anvil systems such as cubic presses.  Wonderstone Ltd. has worked hard to accommodate the special needs of its clients through its ability to machine special shapes to the tight tolerances (± 50 micron) and specifications required.  Products produced for High Pressure High Temperature (HPHT) Processes include all standard products and various technical components used in either Belt Press (bushing, cone gaskets and wings) or Cubic press technologies (cubes, ring sleeves and buttons).

The components can be manufactured / machined from natural stone or reconstituted (powder pressed) using Wonderstone powders in various particle size distributions.  Powders can also be spray dried and / or calcined and utilized in applications in the Belt presses.

Wonderstone Ltd. is proud to announce the development of newly formulated reconstituted components for Synthetic Diamond manufacture. We offer variations on our powder pressed materials in which we are able to produce components suitable for use in both Cubic Press and Belt Press technologies. 

We have performed in depth studies through various Universities and authorities outlining the properties of our reconstituted Wonderstone material.  Our studies have demonstrated a high Weibull modulus, this is indicative of reliability and consistency of the physical properties between batches of manufactured / prepared samples. This means that for reconstituted cubes, when used in diamond capsules, they will yield at the same stress. This happens at the early stages of capsule deformation and are the beginning of the gasket formation stages, thus encouraging the formation of similar-reproducible gaskets.

Some major benefits of Wonderstone as gasket material are as follows:-

* Natural Wonderstone Density ~2.75 g/cm³

* Reconstituted Wonderstone Density ~2.60 g/cm³

* Offers consistency required for cubic gasket components

* Very good thermal insulation

* Excellent pressure transfer capabilities

* Solid gasket seal and elasticity when pressure is released.

These components are exported to synthetic diamond, polycrystalline diamond and cubic boron nitride manufacturers in the UK, USA and Far East and utilised within South Africa.