Jack Lake, Geologist, FGS

01/20/2016

Sorry for the long absence...don't you just hate it when work gets in the way of pleasurable things.
Anyway, I've had a lot of inquiries recently, which I always answer within 24 hours in a private message, about diamonds, simulants and fakes. There are several other minerals and inorganics that are used to simulate natural diamonds, such as quartz, glass, cubic zirconia and such that jewelers use to replace diamond. Also, it's possible to produce diamonds in the laboratory.

Lately, one mineral that's used to replace diamonds is moissanite. This mineral is found in nature, but is quite rare and the cost of finding and fashioning the real thing would end up costing more than a natural diamond. Moissanite makes a beautiful gemstone and there is nothing wrong with buying , selling and wearing this gem. The cost of fashioned Moissanite is about $300.00/carat, while diamond is $1,000.00/carat and up.

One problem in the gemology industry is that some less than honest jewelers will sell something as a diamond and it's not. As long as it's stated up front that the gemstone is simulated, lab-made or what it really is, then there is no problem.

A gemologist or geologist can easily distinguish the difference between moissanite and diamond by a few different tests, such as specific gravity, crystal system and so forth.

One difference between the two is that Moissanite has three times the dispersion that diamond has, which to some people makes it even more desirable. Dispersion is sometimes called brilliance or fire. The test for this is very tedious, but in some specimens can be seen with the naked eye. Below are a few photos of both diamond and moissanite.

The first two are raw and brilliant cut diamond and the second two are raw and brilliant cut moissanite.

02/28/2015

Happy Birthday to all you fine folks who were born this month. This includes Bob Sosnoski and others. Please let me know if this is your birth month. Your birthstone is Amethyst. In my opinion, Amethyst is the prettiest of all the members of the the quartz group of minerals. We have had posts before in regard to the properties of Quartz, but to refresh a little, it is silicon dioxide and also an allochromatic mineral. This means that pure Quartz is clear (colorless). It derives its color from trace amounts of impurities, which are typically elements such as iron and chromium.
A bit of trivia about Amethyst is that it got its name from the old Greek words "a methystos", which translates to "not intoxicated." The ancient Greek people would adorn there drinking vessels with Amethyst gemstones, with the belief that this would not make them drunk. Give it a try and see if it works, if your old enough and not driving.
Below are photos of this gorgeous mineral:

02/22/2015

Another landform that not only is in most cases pleasing to the eye, but offers many recreational activities. Natural lakes are formed by a few different processes, most notably they are glaciation and volcanism. The Great Lakes of the northern U.S. are a good example of lakes formed by continental glaciation. The feature lake of this post is Crater Lake that sits on top of Mt. Mazama in Oregon. This lake formed by the collapse of the crater of the volcano it sits on and fills its caldera. It has not in or out flowing rivers as most lakes do. Gain and loss is from precipitation and evaporation. It is the deepest lake in the U.S. at 1,942 feet deep and formed by the eruption of Mt. Mazama about 7,700 years ago. A photo is shown below.
Do you have a lake that you enjoy? Let us know and post a photo if you can.

02/06/2015

Welcome, Mr. Lahiji! Thank you for following my page. You may ask any question or post any photos you wish that are related to geology on the page. We invite you to get involved.

01/31/2015

LANDFORMS are nearly everywhere we look whether it be driving down the road, flying or looking out the windows of our homes. They can be as simple as a small knoll to a magnificent volcano. Natural arches are one of the landforms that fascinate most people. They are also called natural bridges, rock bridges and sea arches. They are formed by the processes of weathering and erosion. This may be in the form of wave action, moving water, wind erosion and weathering over time. During the month of February I will be discussing some of the landforms that we see and what forms them. If there are any that you would like to discuss, please list them and we will discuss them. Feel free to post photos on this page. Below are some examples of natural arches:

DON'T FORGET THE GIVEAWAY CONTEST ON APRIL 1ST!!!

01/26/2015

A warm welcome to Rick and Betty Snyder who recently started following my page! I hope you enjoy and if you ever have any questions, please ask...that is what this page is for.

01/25/2015

Congratulations to Jeni Minnier! She is now the proud owner of the New Year's give-away...a faceted, pink Topaz. Everyone please give her a round of applause!
The next contest will be on April 1 and another gem/mineral will be given away FREE!

01/15/2015

Happy anniversary to the map that changed the world. This was compiled and published by William Smith (1769-1839), the Father of modern geology. He was scorned and imprisoned by the royalty that controlled what was acceptable by their standards. Years later he was finally honored by all, especially those that scoffed him.

I am particularly honored to hold a similar distinction to his fame. He was and I now share the distinction of Fellow of the Geological Society of London.

Happy 200th birthday to this geologic map,
And thanks for changing the world.

01/12/2015

Happy Birthday to Pamela Mayberry, Ed Ortiz and all of you others that were born this month. If I didn't mention you let me know so that I can acknowledge you. Your Birthstone is Garnet. Garnet is a group of silicate minerals that crystallize in the isometric system. Garnets have been used as jewelry since approx. 5000 BC. It forms in numerous colors and a few samples are shown below.

01/10/2015

This is a close-up photo of the TOPAZ in the GREAT 2015 NEW YEAR'S GIVEAWAY CONTEST. It is a beautiful gemstone. Make your entry...IT'S FREE!

01/08/2015

THE GREAT 2015 NEW YEAR’S GIVEAWAY CONTEST:

A beautiful, pink, trilliant cut TOPAZ will be given away to the winner free of charge and will be shipped free to any location in the U.S. This gemstone would make a beautiful ring for a lady or a nice belly button stud for some lucky guy! The photo shows the actual TOPAZ next to a dime for scale. Photo shown below.)

The rules are simple:
1. You must first like and follow this page to be eligible.
2. You must get someone else to like and follow my page. Send me a private message who you got to “like and follow”. Only one person can use a new individual – first notification gets credit. BONUS – you can make an entry for each new person you get to “like and follow”. In other words, if you get 20 new folks to like my page, you can enter 20 weights.
3. Estimate (guess) the weight of the TOPAZ in carats. A carat is a unit of mass to define the weight of gemstones. Give a weight to the nearest tenth of a carat, for example, 1.3 or 8.9 or 10.0 carats. Remember, for each individual you get to be new to the page you can enter another weight estimate.
The person closest to the correct weight is the winner! If more than one has the same weight, the winner will be determined by drawing. I may add another gemstone as a second prize. My Beagle, GeoCleo, will be the impartial judge.
If you have any questions, please don't hesitate to ask me, either in this thread or by private message.
4. Out of fairness, geologists, gemologists, jewelers and anyone in the business of buying or selling minerals or gemstones are disqualified.
5. The contest ends at noon on Saturday, January 24, 2015.

GOOD LUCK!!!

01/08/2015

Congratulations and thank you to Sharon Rees Wilson for becoming the 50th person to like and follow my geology page. You have won a mineral crystal which will you will receive within a week! Tomorrow I will be posting the the 2015 New Year's Contest giving away a beautiful faceted gemstone...don't forget to enter the contest, Sharon.