|
|
|
|
|
|
|
|
|
|
Calcium makes me think of chalk and orange juice. It's an essential nutrient: Your bones need calcium to grow and stay strong, and milk is a good source, hence the popularity of milk for children. So it might come as somewhat of a surprise to learn that calcium is a reactive alkali earth metal. It's not just a sort-of metal, it's an outright shiny, malleable, machinable metal. It has to be kept under oil or inert gas because it reacts with water (not violently like sodium, but fast enough that it won't last long in moist air). This still seems strange to me, even though I've seen (and hope to get soon) beautiful mirror-bright crystals of metallic calcium.
The explanation of course is that you never see elemental calcium in nature: It exists only as things like calcium carbonate (limestone) and the like.
|
|
| |
|
|
|
|
|
Small lump 99.5%.
Kindly donated by David Franco, who sent many elements after seeing the slashdot discussion.
Source: David Franco
Contributor: David Franco
Acquired: 17 May, 2002
Price: Donated
Size: 0.1"
Purity: 99.5%
|
|
|
|
|
|
|
 10 grams under oil.
I'm hoping to get some really shiny crystalline calcium under argon soon, but this bottle has the advantage of being opened already, so if I want to do any experiments with the calcium, I can get to it without having to break a glass tube. Calcium is fairly reactive in air, so this bottle is filled with mineral oil, which has preserved a fairly clean surface on these metal chips.
When I hear the word "calcium" I, and probably a lot of people, think of a chalky powder, like a calcium supplement pill. But that's a salt, like calcium carbonate (which is, in fact, chalk). Pure calcium really is a metal, lustrous, malleable, the works.
Source: eBay seller flabster
Contributor: Theodore Gray
Acquired: 3 January, 2003
Price: $10.50
Size: 1"
Purity: >99%
|
|
|
|
|
|
|
|
|
|
Sample from the Everest Element Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (excepted gasses) weight about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.
To learn more about the set you can visit my page about element collecting for a general description and information about how to buy one, or you can see photographs of all the samples from the set displayed on my website in a periodic table layout or with bigger pictures in numerical order.
Source: Rob Accurso
Contributor: Rob Accurso
Acquired: 7 February, 2003
Price: Donated
Size: 0.2"
Purity: >99%
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
