Radium stimulates powerfully various mineral and chemical substances
near which it is placed. It is an infallible test of the genuineness
of the diamond. The genuine diamond phosphoresces strongly when brought
into juxtaposition, but the paste or imitation one glows not at all.

It is seen that the study of the properties of radium is of great
interest. This is true also of the two other elements found in the
ores of uranium and thorium, viz., polonium and actinium. Polonium,
so-called, in honor of the native land of Mme. Curie, is just as active
as radium when first extracted from the pitchblende but its energy
soon lessens and finally it becomes inert, hence there has been little
experimenting or investigation. The same may be said of actinium.

The process of obtaining radium from pitchblende is most tedious and
laborious and requires much patience. The residue of the pitchblende
from which uranium has been extracted by fusion with sodium carbonate
and solution in dilute sulphuric acid, contains the radium along with
other metals, and is boiled with concentrated sodium carbonate solution,
and the solution of the residue in hydrochloric acid precipitated with
sulphuric acid. The insoluble barium and radium sulphates, after being
converted into chlorides or bromides, are separated by repeated
fractional crystallization.

One kilogram of impure radium bromide is obtained from a ton of
pitchblende residue after processes continued for about three months
during which time, five tons of chemicals and fifty tons of rinsing
water are used.

As has been said the element has never been isolated or separated in