The "Golden Jubilee Diamond" at 545.67 carats is the largest finished
diamond in the world.  By a very large margin.

And the Koh-i-Noor (105.6 carats) isn't the second, third or even 15th
largest finished diamond.  Not by a long shot.

The "Cullinan I" or the "First Star of Africa" weighs 530.2 ct

And the "Cullinan II" or the "Lesser Star of Africa", weighs 317.4 ct.

"Spirit of de Grisogono" (found is west central Africa), weighs 312.24 ct.

The "Centenary Diamond" (btw, also NOT found in India) weighs 273.85 ct.

"Jubilee Diamond", 245.35 ct.

"Millennium Star", 203.04 ct.

"La luz de dia", 201 ct.

"Orlov", 189.62 ct.  

"Jacob Diamond", 184.5 ct.

"Darya-ye Noor", 182 ct.

"Paragon Diamond", 137.82 ct.

"Florentine Diamond", 137.27 ct.

"Premier Rose Diamond", 137.02 ct.

"Tiffany Yellow Diamond", 128.54

"Star of the South", 128.48 ct.

"Portuguese Diamond", 127.01 ct.

Yeah, right.  India has been an "international market place for diamond
jewelry", since 1000 BC

"All the big Diamonds those you can think about are from India."
The first one I can think of, and the largest diamond ever found is the
Cullinan, found in Cullinan South Africa in 1905

The "Excelsior Diamond" was found in 1893 at the Jagersfontein Mine in
South Africa and was the largest diamond ever found until the Cullinan
was found.

The third one I can think of is the "Oppenheimer Diamond" from
Kimberley, South Africa.

The "Lesotho Promise" was found in, you guessed it Lesotho in 2006

I could go on for a while, but that would become boring.