70 
compact in some parts as to give this stone a particularly 
solid and glassy appearance, but in those parts they may 
nevertheless be easily separated, even by the finger nail. 
As Gypsum dissolves sparingly in water, the speci- 
mens cannot be washed without great care, and brushing 
scratches them; even the common air spoils their ap- 
pearance, which is worth preserving: they should therefore 
be kept very attentively. 
