An exceptional 15 carat heart shape pink diamond and a 213ct top-colour white diamond were on show last night at the WA Museum Boola Bardip in Perth.
Recent auction sales of comparative diamonds place the combined value of the stones at more than US$10 million.
The museum's iconic giant blue whale changed colour to pink for the occasion.
A 46ct pink gem was recovered at the Lulo mine in Angola and was polished into the 15ct gem on display. Lucapa recovered the 213ct rough white diamond from the Mothae mine in Lesotho.
"You can't help but think about the incredible beauty and magnitude of nature when you see large and exceptional billion-year-old diamonds like these two rare stones," Lucapa CEO Stephen Wetherall said.
"Our two mines in Africa are uniquely rare in that they are expected to produce valuable stones regularly, however the two days on which these recoveries were made was filled with just a little bit more excitement, truly special days for our site team members and our mine partners.
"The shareholders of Lucapa have provided us with the ability to invest in Africa with our partners for almost two decades now, so as important as these discoveries are to Angola and Lesotho, they too are important for Australia."
It has been a big week for Lucapa, which raised A$20 million to fund the acquisition of the Merlin diamond mine in the Northern Territory.
"Now that the Argyle mine has closed down, Australia has no diamond producers," Wetherall said.
"The Merlin mine has not operated for a number of years, but we are hoping to change that soon."
Lucapa shares closed at 5c yesterday, valuing the company at $41.65 million.