Famous Topaz Gemstones Cut and Uncut

Topaz is a silicate mineral which is the largest and most important class of rock forming minerals. Topaz belongs to the sub class nesosilicates the simplest of all silicates in which the tetrahedral SiO4 units exist separately but are held together by metal cations as in garnets andalusite and olivine or form cross linkages between chains of octahedrally co ordinated aluminum cations and do you know that some of the finest gem rough stones in the world.

The Golden Topaz Sphere, the 2nd Topaz listed on this webpage, weighing a whopping 12,555 carats, with over 1,000 facets is said to have been cut from a rough stone originating in Minas Gerais, Brazil, by a gem cutter in Idar-Oberstein, Germany. The sphere is exhibited side by side with the 22,892.5-carat American Golden Topaz, the 3rd largest faceted topaz in the world, in the Hall of Geology, Gems and Minerals of the National Museum of Natural History of the Smithsonian Institution.
A photograph of the Golden Topaz Sphere exhibited just behind the American Golden Topaz at the museum, is given below for the benefit of participants in this forum.

Images of all gemstones listed in the webpage "Famous Topaz Gemstones Cut and Uncut" might be timely and informative for the ongoing discussion. I am uploading images of these gemstones in the order in which they appear on the webpage.

1) American Golden Topaz
2) Golden Topaz Sphere - images already uploaded by Johnruby

3) The Lindsay Uncut Topaz weighing 32kg (70 lbs) - the shorter crystal
4) The Freeman Uncut Topaz weighing 50.5kg (111lbs) - the longer crystal

5) El-Dorado Topaz - 31,000 carats (6.2kg), Largest faceted topaz in the world from the Programa Royal Collections

Thanks Mary for uploading the images of the Famous Topaz Gemstones Cut and Uncut, particularly the latest images of the El-Dorado Topaz from the Programa Royal Collection.
Images of three more Famous Topaz Gemstones, from the Programa Royal Collection are uploaded below :-
6) "Lua de Maraba" Topaz - 25,250 carats; 2nd-largest faceted topaz in the world; rare, grey-colored, octagonal-cut topaz.
7)Topaz Amarelo - 9,600 carats; 6th-largest faceted topaz in the world; 3rd-largest faceted topaz in the Programa Royal Collection, pear-shaped, yellow topaz; largest pear-shaped topaz in the world.
8)Topaz Azul - 8,225 carats, 7th-largest faceted topaz in the world; 4th-largest in the Programa Royal Collection; originally colorless, yellow or yellowish-brown; converted to intense blue by irradiation; largest irradiated blue topaz in the world.

According to the internetstones.com blog webpage - List of Famous Faceted Topaz Greater than 1000 Carats in Weight - out of the 15 famous faceted topaz listed, 8 belong to the Programa Royal Collection (PRC), five to the Smithsonian's NMNH and one to New York City's AMNH. The 7th-largest faceted topaz according to this list is the 8,225-carat Topaz Azul (Blue Topaz), belonging to the PRC, the largest irradiated blue topaz in the world. Elsewhere, I have come across another 8,225-carat blue topaz also belonging to the PRC known as the Marbella Topaz, said to be the largest blue topaz in the world. Is it possible to have two blue topazes of exactly the same weight and color in the same collection or was the Topaz Azul renamed the Marbella Topaz at a later date ?

Topaz Azul and Marbella Topaz have exactly the same weight of 8,225 carats, and have the same intense blue color caused by irradiation. A comparison of the images of the two topazes show that they are exactly identical, and as you have suggested it is highly likely that the Topaz Azul was subsequently renamed the Marbella Topaz.
The massive 8,225-carat, blue topaz with its perfect cushion-cut and intense deep blue color was actually in the possession of the PRC since April 2000 when it was purchased from Russian dealers at the Gem & Mineral Show in Tucson, Arizona, USA and was added to the "Special Exhibition Gems Collection" under the name Topaz Azul. However, on July 14, 2010 the enormous irradiated blue topaz was christened the "Marbella Topaz" by the PRC on a request made by the Marbella Town Council and its Mayoress, with a view of stimulating the town's economy, encouraging its cultural development and also raising the town's profile internationally when the stone is exhibited in a number of different countries as part of the "Special Exhibition Gems Collection."
The following images of the "Marbella Topaz" bring out the beautiful characteristics of the stone, such as its perfect clarity and cushion-cut, and the intense deep blue color

Apart from the commonest colors of yellow, yellowish-brown, golden-brown, pale-blue and colorless, in what other colors do natural topaz exist ?

Most famous oval shaped Marbella' topaz weighs around 8,225-carats and known for its perfect color and cut, although 31,000 carats 'El Dorado' topaz is highest in weight.