The result compared with a $4.3 million loss for the first half of 2018 and came despite a challenging period for the diamond sector.
Diamond sales for the half were $29.4 million, including $22.1 million from the Lulo mine in Angola.
At the new Mothae mine in Lesotho, diamond carat production was 36% ahead of plan, while operating costs were 14% below forecasts.
Lucapa said it was poised for a stronger December half as mining at Mothae transitioned to higher margin diamond zones and Lulo expanded.
The company reported record months in August for both operations.
Lulo produced 3,180 carats, the highest monthly result since production started in 2015.
A significant factor contributing to the result was the monthly grade of 13 carats per 100 cubic metres, which is almost twice the planned grade of 6.7 carats per 100 cubic metres, and was achieved from two new mining areas not previously subject to artisanal activity.
Mothae produced two records during August. A monthly processing record of 120,736 tonnes treated was achieved, recovering a record 2911 carats, taking year to date carat production to 17,935 carats.
Lucapa shares last traded at A15c, just above a 52-week low of 14.5c. The stock was at 26.5c a year ago.