DANBURITE

A rare silicate of calcium and boron which may appear a variety of colours including brown, gold or pale pink. (It may also be colourless) It may sometimes show different colours depending on the angle from which it is viewed. This characteristic is known as pleochroism and enhances it's appearance. It is fairly hard, measuring 7 on the mohs scale.

It may occur in large lumps of crystals some of which may resemble topaz. The main difference is that topaz has perfect cleavage whereas danburites cleavage is poor. It is not usually used as a gemstone because it is easily damaged although it can be shaped into beautiful display pieces.

Danburite was first identified in 1839 and was named after the town of Danbury, Connecticut, US where it was first discovered.

It is fairly widespread but occurs in small quantities alongside feldspar in deposits of dolomite. It can be found in Danbury (US), Mexico, Burma, Japan and Switzerland.

KAINITE

A very rare sulphate which is usually colourless. Crystals can sometimes be found in rock cavities but it usually appears in solid lumps in layers with other salts e.g. rock salt and gypsum. When it lies with rock salt it may become grey, blue, violet or yellow. It has an unusual chemical composition and contains potassium, which can be used in chemical fertilizers. It also contains magnesium and chlorine but only potassium is industrially extracted.

It is a member of the evaporite group of minerals and forms when salt water evaporates leaving solid matter behind which eventually turns into rock. Therefore it can be concluded that the land where it is found was probably under water at one time. It is sometimes found at locations where rivers flow into enclosed lakes. Deposits may then be covered by new layers of rock as the earth shifts. Other examples of evaporites include gypsum (used in plaster of Paris) and halite (used as table salt).

It is very soft (3 on the mohs scale) and therefore is of no value as a gemstone. It dissolves in water and turns to liquid in moist air which is known as deliquesence.

Main deposits are in Germany, Poland and Ukraine. It can also be found in Italy and US.