Hoppered cubic Halite crystals. Searles Lake, California, USA
Everyone has come across halite at some point. It is better known as rock salt, or table salt and has the chemical formula NaCl. You've probably eaten it on chips and learnt about it in science classes.
This sample comes from Searles Lake in California. Searles lake is in the middle of the mojave desert. It is a dry lake, but small amounts of water drain in into it throughout the years. As the water evaporates off, it leaves behind evaporite minerals. Halite forms seasonally in this environment, but the area is most important for the commercial extraction of minerals such as borax.
Like all halides, halite has a cubic habit. it makes little cubic crystals which often break cleanly into smaller cubes. this sample is demonstrating "hoppering". the crystals grew a little too quickly, there was only time to grow the edges of the material, but not enough time to grow the faces. bismuth crystals do the same thing and if you hold a bismuth crystal next to one of these samples, you will see some similarities.
The distinctive pink colour of these crystals is due to the presence of salt loving archea and algae. These tiny miscroscopic organisms contain carotenes which stain the halite. Believe it or not, this is also the reason why some flamingos are very pink, they feed on algae which contains carotenes and this leads to the pigment of their feathers.
this item is 63g. The photograph is of the item offered for sale.