Two months' ago the valuation was just a third of what it is now.
The re-rating is on the back of strong ruby recovery rates and the planned expansion of its processing plant at the Montepuez Ruby Project in northern Mozambique.
The improved operating structure has provided Mustang with 405,000 carats to show case at its maiden tender this week, more than double 200,000 carats it initially targeted when setting the sale date.
Christiaan Jordaan, managing director, commented:
"We originally set an aspirational target of 200,000 carats and we have now doubled it.
"This is a pivotal result because it demonstrates the quality of our project and its enormous potential.
"It is increasingly clear that Montepuez can generate production and cashflow on a much greater scale.
"We also believe that our upcoming exploration program will establish that we can sustain increasing production over a considerable number of years."
A total of 42 leading ruby buyers from around the world have registered to attend this week’s tender, which will be held between 27 and 30 October 2017 in Port Louis, Mauritius.
The buyers come from Thailand, India, Sri Lanka, Hong Kong, the United States and Europe.
Mustang will then outline the results of the tender when it is completed and the sales have been collated.
Following the tender, Mustang plans to make the next upgrade to the processing plant at Montepuez.
This provides a new target of 1,000,000 carats of ruby sales in CY2018 via two tenders.
Mustang is now a significant participant in the global ruby market, with ethically sourced stones.
The timing of the increased production has married up with global ruby demand, positioning the company as an in-demand stock as world’s only publicly-listed ruby miner.