The phrase "although not discovered" is correct and usable in written English.
It can be used to introduce a contrast or exception regarding something that has not been found or identified.
Example: "The ancient ruins were believed to hold many secrets, although not discovered by archaeologists yet."
Alternatives: "even if not found" or "despite being undiscovered".
Although germanium was not discovered until 1886 by Clemens Winkler, a German chemist, its existence, properties, and position in the periodic system had been predicted in 1871 by the Russian chemist Dmitry Ivanovich Mendeleyev, who called the hypothetical element ekasilicon.
The Americans, who are aware the meetings have taken place – although they have not discovered the details – are sure to fight this international cabal which will include hitherto loyal allies Japan and the Gulf Arabs.
By the end of his life, Tillson Harrison could speak no less than six different languages, had participated in seven wars and, although this was not discovered for several years after his death, was married to four women at the same time.
James Rivington, the editor of that publication, may also have served as an agent for the Continental Army, although that possibility was not discovered until 1860 and is still debated.
Actually, the alleged safety of malathion rests on rather precarious ground, although — as often happens — this was not discovered until the chemical had been in use for several years.
Interestingly, although P-type like accessions were not discovered in the investigated germplasm, another genetic substructure with no correlation to geographic origin was evident within B. vulgaris, with three accessions (4, 8, 27) forming a distinct group.
Sierra Leone, although surrounded by Guinea and Liberia, had not discovered a single confirmed case.
Genotyping evidence strongly suggested transmission from one species to another, although corroborating epidemiologic evidence of transmission was not discovered.
Although the planets Uranus and Neptune were discovered in 1781 and 1846, Pluto was not discovered until 1930.
Lysergic acid diethylamide was first synthesized by the Swiss scientist Albert Hofmann in 1938, although he would not discover its illuminating effects until five years later, when he unknowingly handled and then ingested a small amount.
