MINERALOGY - THE ELEMENTARY COLLECTION

Minerologie is an ongoing research project of a digitalized engyclopedia of minerals.

Many minerals, instead of growing as single and distinctly developed crystals, give rise to various, more or less, accidental shapes and various kinds of structure or texture, due to the crowding together of a large number of crystal individuals. Although this, of course, complicates the study of the crystals themselves, yet these forms of aggregation are often extremely characteristic of particular minerals.

When the material consists of a vast number of minute crystalline individuals closely crowded to- gether, and each individual is developed to approxi- mately the same extent in all directions, we have a granular crystalline structure. Here the crystalliza- tion of the material had clearly started simultane- ously at a large number of neighboring centers, and all the intervening spaces soon became filled up, forming a mass of crystalline grains, but without the development of any crystal faces. Such a structure is well shown by statuary marble and by loaf-sugar; on fractured surfaces of these materials the extent of each crystalline individual forming the mass is readily seen when the bright cleavage surfaces are examined with a magnifying-glass. If the crystal- line grains are so small that they cannot be dis-tinguished, except under the high powers of a mi- croscope, the structure is described as compact, and the mineral is said to be massive.
 
Autonomous / Research work
DATE : 2022