Minerals of India
The state of Maharashtra in India has provided an abundant supply of zeolites and other minerals that have come out of the enormous lava flows called the Deccan Traps. The traps are arguably the largest volcanic feature on the earth. They consist of hundreds of layers of flood basalt over 6,500 feet thick, which cover almost 200,000 square miles - larger than the state of California. Basalt quarries in this region produce hundreds of tons of mineral specimens every year, creating a glut that keeps the price for most of these pieces amazingly low. Zeolites are a popular group of minerals to collect because they are so beautiful and because they contain such diversity in color, crystal form and rarity (some are very common and inexpensive to collect and some are rare, costly, and a pleasure to finally own). Most all the specimens come from basalt quarries which provide material for the building boom that has gone on in central India for the last 40 years. Others are found when wells are dug and when construction projects for buildings and roads require blasting.
Zeolite minerals in India are found in amygdaloidal vesicles (called cavities or pockets) in the Deccan lava flows. Zeolites are secondary minerals made up of hydrated aluminum silicate molecules that readily join with cations such as calcium, sodium, or potassium. The word zeolite comes from the Greek zeo (boil) and lithos (stone). The term was first used in 1756 by Axel Fredrik Constedt, a Swedish mineralogist, who found that when heated, stilbite gives off large amounts of water vapor that was locked in the mineral's structure. Today, over 194 aluminum silicate zeolite minerals have been identified.
The Deccan Traps formed 60 to 70 million years ago, during the late Cretaceous period. They were formed by volcanic eruptions, which may have lasted only 30,000 years. They were caused by a deep mantle plume called the Réunion hot spot, that has been connected to the movement of the Indian tectonic plate. Hundreds of volcanic eruptions occurred, flooding an area the size of modern day India with multiple low viscosity flows that varied in thickness from three feet to over 50 feet. As the lava cools, bubble-like fluid and gas vesicles form and merge, and are trapped under the rapidly cooling surface of the flow. As the lava cools and becomes basalt, minerals migrate to and crystallize in these voids, forming the wealth of mineral specimens for which India is justifiably famous.
COLLECTING IN INDIA
Throughout the state of Maharashtra, there are thousands of quarries being worked and wells being dug at any one time. Because they cannot be everywhere that digging is going on, a "runner" system has evolved as a way for dealers to keep an eye on many of the possible localities for high quality minerals.
It is the runners who are usually recognize and preserve India's fine mineral specimens. They show up at the working quarries and well sites whenever there is a blast, so they can pick up, trim and pack the specimens. They work with the miners, pointing out promising zones and telling them about the value of the specimens. Our runners usually buy specimens, and then sell them to us. Most specimens are trimmed by the runners before they are sold. Specimens are often trimmed with a diamond saw, then worked with a hammer and chisel to hide the saw marks.