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drugs. This applies even when the drug is in powdered form because many
of the crystals remain intact. These different forms may be classified into:
1) Prisms e.g. in Quillaia and in the crystal sheath of senna, cascara

and frangula.
2) Cluster crystals: These are aggregate crystals composed of

numerous prisms or pyramids or both, which have grown together to
form more or less spherical masses with projecting points and angles
all over the surface, as in senna, cascara ……..etc.
3) Rosettes: They are aggregate crystals having the appearance of a
fairly large center which may be partly organic, from which the
component crystals radiate, and so nearby equal in length as to give
a slightly toothed circumference e.g. in aleurone grains of
Umbelliferae. Etc.
4) Acicular or needle-shape crystals: Very narrow, slender, long
crystals, with pointed end, commonly occurring in bundles;
frequently embeded in mucilage within the cells as in squill or
sometimes in cells devoid of mucilage as in lpecacuanha,
Sarsaparilla etc. Small needles, scattered and not in bundles, are
found sometimes, termed raphides.
5) Microcrystals or sandy crystals: These are very minute crystals
often occurring in cells in large numbers, frequently completely
filling the cell. The form of the individual crystals may vary in
different plants; in cinchona the sandy crystals are small prisms.

2. Calcium Carbonate:

Calcium carbonate may be found embeded in or incrusted in the cell
wall. Concentration of calcium carbonate formed on outgrowths of the cell
wall termed cystoliths e.g. cystoliths of the enlarged upper epidermal cells
and covering trichomes of Cannabis. It can be identified by its solubility

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