This month I had the opportunity to meet up with some
friends and visit Searles Dry Lakebed in Southern California for the 75th
annual Gem-O-Rama. Gem-O-Rama is a two
day gem and mineral collecting festival hosted by the Searles Lake Gem and
Mineral Society every year during the 2nd weekend in October. During this event there are three field trips
to collect rare and beautiful minerals from the lake bed. My friends and I participated in all three of
the trips and were able to collect some pretty cool stuff!
About Searles Dry Lakebed:
Searles Dry Lakebed is what remains of an ancient lake that
existed during the last ice age. The
climate during this time was cooler and wetter causing many large lakes to form
in the American southwest. Because of
the geologic formations in this area the lakes had no outlet rivers to take
water out of the lake. With no outlet
rivers to ‘flush’ the lakes they became very concentrated in certain minerals,
especially salts, which were dissolved in the water. Later, when the climate became hot and dry
again, the lakes evaporated leaving the minerals behind. In the case of Searles Dry Lakebed, the
conditions were perfect to form a variety of amazing mineral specimens. Today, the lake bed is mined by Searles
Valley Minerals for these minerals which are used in a wide range of common
items such as detergents, glass, cosmetics, anti-fungals, fire-retardants, and
fiberglass. Once a year, for Gem-O-Rama,
the mining company allows participants onto the lakebed to collect their own
minerals.
View from the lakebed
The Mud Field Trip:
For the first field trip almost 200 tons of sticky black mud
are dug up from 10-20 feet below the surface of the lakebed and spread out into piles on the surface. The 800 participants then get to dig through
the mud looking for mainly Hanksite among a few other minerals.
People from all over the world come out for Gem-O-Rama. Searles Dry Lakebed is where Hanksite was
first discovered and is only found in a few other locations in the world.
My friends searching through the mud for crystals.
The mud makes it hard to tell if you have a good
specimen. However, you can’t simply wash
them off with water. Because they’re a
type of salt they end up dissolving! In order to clean them you have to use
brine.
Troughs of brine are available to wash off specimens.
Hanksite, which is a sodium potassium carbonate sulfate
chlorite, is shaped like a cylindrical hexagon with two hexagon pyramids on
each end.
The Hanksite found here is called ‘barrel’ Hanksite because it looks
like a barrel.
The Blow Hole Field Trip:
A week before this field trip multiple holes are drilled 25
to 40 feet below the surface of the lake bed and explosives are set to loosen
the minerals making it easier to bring them to the surface. A couple days before the trip pumps are used
to bring the brine containing the minerals up to the surface and are spread out
for participants to search for Hanksite, Sulphohalite, Borax, Halite, and Trona.
Pumping the brine and minerals to the surface.
Searching through the debris.
Close-up of the debris, can you spot anything cool?
The Hanksite from this depth is called ‘doubly terminated’ because the
two pyramids on the end terminate at a point
Sulphohalite is another mineral that was first discovered at Searles
Dry Lakebed, it forms two pyramids
Borax, commonly used in detergent, reacts with air to form a chalky
white coating over time.
Halite, also known as table salt, forms cubes.
Trona forms in large clumps of little ‘blades’. If you ever participate in Gem-O-Rama be sure
to wear gloves to prevent the Trona from cutting you!
The Pink Halite Field Trip
During the final field trip there is only one mineral to be
found and as the name suggests it’s pink Halite! Halite, which is regularly clear, can be
tinged pink by salt-loving bacteria that turns red when it dies. This field trip is located at the south end
of the lakebed where rain water from the previous winter collects. The water (also known as brine) contains a
lot of dissolved salt and is the perfect home for salt-loving bacteria. During the summer the water evaporates making
the water saltier and saltier. Eventually, the bacteria die turning the water
red. At the same time large salt
crystals begin to grow around the edges of the brine pools, like ice on a
lake. The salt incorporates some of the
dead bacteria turning it pink.
The best crystals are found on the bottom side of the salty crust that
covers the brine pools, it can be hard work to break through!
After some trial and error we finally found a good pool.
Pink Halite, like regular Halite, grows in cubes but sometimes the
crystals aren’t well formed because they grow very quickly.
If you like rocks and ever get the opportunity to go to
Gem-O-Rama I would definitely recommend it! My friends and I had a blast and
were able to add a bunch of new minerals to our collections. Even if you aren’t a geologist or don’t know
what you’re doing there’s sure to be someone who will be more than happy to
give you pointers. Plus, no matter your
age or experience, you’re almost guaranteed to find something cool! Be prepared to get dirty and have a lot of
fun! I also want to give a huge thank
you to Searles Lake Gem and Mineral Society and Searles Valley Minerals for all
the work they put into making this happen!
