Below 100 C, these crystals will melt in their own water of crystallization and will tend to lose water slowly.

Tests show that crystals tend to be larger and more ordered internally when their growth is not skewed by gravity.

Since light reflects from the grain boundaries (boundaries between crystallites), larger crystals tend to be transparent, while the polycrystalline aggregates look like white powders.

The crystals tend to be long thin blades that typically form radial aggregates, and sometimes fans and tufts.

Colorless crystals tend to be transparent while colored specimens have varying degrees of transparency.

The new crystals tended to be long, smooth, whip-like filaments, initially so thin that they were hardly visible in the optical microscope.

Informally, two crystals tend to be in the same crystal system if they have similar symmetries, though there are many exceptions to this.

The crystals as found tend to be large and irregular in shape.

Tabular crystals tend to lie along the film's surface when coated and dried.

The crystal tends to grow at the edges and not on the main planes, forming very thin crystals of very large surface areas.