Although the solubility product values of calcite and witherite
are very close, about [10.sup.-83]-[10.sup.85] subjected from temperatures, witherite
as a member of the aragonite group is less stable than calcite, and during dissolution its saturation in solution will not be reached.
Following the 1889 meeting of the British Association for the Advancement of Science, for example, he made the rounds in Cumberland with "a leading mineralogist," acquiring "butterfly" calcite, barite, fluorite, witherite
However, when the higher barium-content witherite
from nearby Nentsberry came onto the market, the demand for the lower-quality Blagill material disappeared and there are no production records after 1895.
He said: "I've kept three scrap books of old photographs, old drawings of the mine workings, pieces of Witherite
and I've still got the sign from one of the steam engines in the Ellen Shaft.
Although exploratory work revealed good witherite
ore in the lower 90 feet of the old lead workings, witherite
was never mined there.
The Hilton mine is unusual in being situated on the margin of the fluorite zone, where barite and witherite
would normally have predominated.
In the 1850s the Caldbeck mines were yielding wonderful lead and copper minerals, and some of the world's finest fluorite and witherite
was being found in abundance in the Northern Pennines.
Catalog C once contained several specimens of witherite
from Anglezark in Lancashire, where it was first found in the late 18th century, though only Georgiana's specimens from Arkendale in Yorkshire have been identified to date.
The Baumann prospect, once explored for its barite potential in the late 1920's, hosts a number of barium minerals including alforsite, barite, bazirite, benitoite, celsian, fresnoite, hyalophane, krauskopfite, macdonaldite, sanbornite, titantaramellite, walstromite, witherite
and two new minerals which are currently under study.
Associated minerals are: celsian, fresnoite, macdonaldite, pyrrhotite, titantaramellite, traskite, witherite
, two new minerals and a hydrated form of Si[O.sub.2].
The mineral deposits which lie beneath the Pennine Hills of Northern England have been mined for centuries and are known to collectors worldwide for fine specimens of fluorite, barite and witherite
. The ancient lead mining district of Alston Moor, which lies on the northwestern edge of the North Pennines, has also furnished exceptional examples of two mineralogical rarities: the barium-calcium carbonates alstonite and barytocalcite.
But the gallery is totally lacking in fine barite, bournonite, witherite
and liroconite, and even the Weardale fluorites left much to be desired.