Etch patterns produced on habit rhombohedral faces and rhombohedral cleavages of amethyst crystals are described and illustrated. Fidelity of etchants used is assessed. Also described are paired pits produced on match cleavages etched with the same or different etchants. By prolonged etching experiments it is established that the dislocations penetrate into the body of the crystal. Spatial distribution of dislocation in the body of the crystal is worked out. Uniformly spaced etch pits in an array observed on match cleavages (etched with different etchants) are attributed to low-angle tilt boundaries.

Lead carbonate whiskers were grown by diffusion of ammonium carbonate in the silica gel charged with lead nitrate. It is found that low pH is preferred to the whisker growth. In addition to straight whiskers gently curved whiskers are also found. Curving of whiskers is found to be maximum at high concentration of carbonate ions. Growth kinetics of whiskers are studied by changing the parameters of gel growth. It is found that the parabolic relationship between dimension and growth period is obeyed in this.

The effect of impurities on the growth of manganese carbonate crystals has been studied. Stereophotogrammetric analysis showed that all crystal faces have the same Miller indices$$\left\{ {10\bar 11} \right\}$$ and the peanut-shaped forms are twins with twin axis 0001.