As crystals, and as stalactitic, encrusting, reniform, massive, earthy and occasionally pulverulent forms as "sulphur meal."
Within the perianth, and springing from its sides, or apparently from the top of the ovary, are six stamens whose anthers contain pulverulent pollen-grains.
Sometimes the metal is deposited in a pulverulent form, at others as a firm tenacious film, the nature of the deposit being dependent upon the particular metal, the concentration of the solution, the difference of potential between the electrodes, and other experimental conditions.
Burnt deposits are dark-coloured, or even pulverulent and useless.
(c) The crustaceous thallus, which is the most common of all, forms a mere crust on the substratum, varying in thickness, and may be squamose (in Squamaria), radiate (in Placodium), areolate, granulose or pulverulent (in various Lecanorae and Lecideae).