If carbonado came from space, it came inside something. The 2006 paper by Garai and colleagues describes the parent as a fragmented body “of asteroidal proportions”[1], and the NSF announcement spoke of a body “a kilometer or more in diameter”[2]. Haggerty’s review proposes two alternatives: a large diamond meteorite, or smaller diamond “plums” carried in a carbonaceous meteoritic matrix[3].
The scale is constrained, loosely, by how much carbonado exists. Haggerty estimates the recovery from Brazil and the Central African Republic at roughly two metric tons[3]. Individual stones can be large: four of the five largest diamonds reported from Brazil are carbonado, and the largest, the Sergio, recovered in 1905, weighed 3,167 carats, heavier than the 3,106-carat Cullinan rough[3].
That quantity is also an argument against one terrestrial model. Haggerty notes that an impact origin would require a carbon-rich target several cubic kilometers in volume, uncontaminated by crustal material, to yield two tons of carbonado[3].
ASA Digital Art’s speculation, not a published finding: the original mass may have been enormous—perhaps comparable to a skyscraper—before collisions in space broke it apart. The sources above support a large parent body; the skyscraper comparison and the collision sequence are ours and have not been tested.
Two cautions follow. First, no parent body or host rock for carbonado has been found[3]. Second, the size figures in the literature are part of the space-origin hypothesis itself and stand or fall with it.