Having the shape of a needle: acicular crystals. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "acicular" in a sentence
"One I like to point to as an example is "acicular" which goes:"
"Soon Birdie and myself were a mass of acicular crystals; it was a true easterly fog."
"One fissure was completely lined with exquisite, acicular crystals of sulphur, which perished with a touch."