The phrase "although vast" is correct and usable in written English.
It can be used to introduce a contrast or exception regarding something that is extensive or large in scope.
Example: "Although vast, the desert is home to a surprising variety of life."
Alternatives: "despite its size" or "even though extensive".
Restored gravel pits have been important new wetland habitats, although vast swaths of fen and marsh were drained in previous centuries.
Jon Corzine, the junior senator from New Jersey, has already demonstrated that unrestrained spending of personal wealth can win an election, although vast riches do not guarantee success.
Although vast, the amount of water contained in the shelves themselves is insignificant in terms of its impact on sea level rise.
"Although vast sums of money are spent collecting migration and border control data, very few agencies collect and publish data on migrant deaths," said Frank Laczko, the author of Fatal Journeys, and IOM's director of migrant research division.
Although "vast demonstrations of solidarity will make little or no impression on the terrorists … it is essential to demonstrate as loudly as possible... that, for all the handwringing about western society's decadence, it retains core values of decency, compassion and tolerance".
Although vast logs of such activity are routinely captured, there is currently little or no understanding of how to predict behavior from the logs.
Although the vast assemblage sported many unfamiliar faces, and although some important familiar ones were missing, Mr. Vonk pulled the group into a convincing and sonorous whole.
Although this vast work (Isidore of Sevilla [c.
Leonard said that although this vast improvement was possible, it would be very hard to achieve.
Although the vast majority of colonoscopies involve sedation, sedation is not required in every case.
Although the vast majority of homes are owner-occupied, there are some available for rent.
