He invented a machine for the cutting of crystals from calc-spar.
It is harder than gypsum, but not so hard as calc-spar; flexible and elastic; spec.
It is considered by Dr. Feussner to be the most perfect prism capable of being prepared from calc-spar.
The end surfaces and also the cut carried through the prism are parallel to the principal axis of the calc-spar.
The external form of the prism may thus be similar to the Hartnack, the calc-spar being replaced by glass.
The minerals composing the veins are either quartz, calc-spar, or sulphate of baryta.
calc-spar will not supply the place of flint, nor lead the place of steel, in the production of fire by collision.
Its beds are from one to two feet thick, and much intersected by small veins of calc-spar.
Argentine, a silvery-white slaty variety of calc-spar, containing a little silica with lamin usually undulated.
It is usually whiter than the Headon limestones, and the fossils occur as casts, the shells being sometimes replaced by calc-spar.