acicular

In a pair of reports from 1957 and 1958, the lab said the talc contained “from less than 1 percent to about 3 percent of contaminants,” described as mostly fibrous and “acicular” tremolite.

Minute acicular or dendritic crystalline forms sometimes observed in glassy volcanic rocks.

In this disease cartilage, ligaments, and tendons, bone-marrow, muscle, the endocardium and aorta, the membranes of the brain and spinal cord, the skin and kidneys, may contain deposits of acicular crystals and amorphous granules.

Much of the calcium in sea-water exists as sulphate; and on evaporation of a drop of sea-water under the microscope this sulphate is deposited as acicular crystals of gypsum.

The plumbago occurs both amorphous, and in long acicular crystals.