The Arthur Ross Terrace will be closed this morning, Tuesday, October 21, for a private cultural observance. You many observe smoke and/or fire coming from the Terrace at that time. The FDNY has been notified in advance, and all safety precautions are in place. The Terrace will reopen at 1 pm.
In warm and arid climates, water evaporating from landlocked, or playa, lakes may result in the development of various minerals. As the lake waters evaporate, they become naturally enriched in the different soluble chemicals carried into them by streams. These chemicals have been obtained through weathering and erosion of nearby rock materials. Continued evaporation concentrates these chemicals to the point where they precipitate and accumulate at the bottom and shores of lakes as a group of distinctive minerals.
Here, we are dealing with the physical environment in which the minerals are formed right at the Earth's surface through the simple process of water evaporation. The evaporite environment of mineral formation occurs usually in regions where the humidity is quite low, the Sun's temperature is quite high, and streams containing the necessary dissolved elements are able to flow into lakes to enrich the lakes with elements. If the lake has no outlet, it will lose its water content simply through evaporation. The dissolved elements, brought into the lake by the streams, become progressively more and more concentrated and begin to crystallize out at the bottom of the lake or along the shore regions of the lake.
These evaporite minerals, as they are called, are here arranged into two groups. Those that are the alkalic minerals, containing such distinctive minerals as halite, or common ordinary salt, gypsum, trona, and other minerals that are displayed in the first case to your left. The second case contains minerals that are rich in boron, and this is the borate collection. Minerals, such as borax, a mineral that is used as a cleansing agent, krennerite and bakerite and ulexite, are minerals that are typically borate minerals.