In honor of going rock-shopping at the annual gem and mineral show, I figure I ought to show off some of the pretty things in my collection. I don’t have anything particularly valuable or unusual, but I do have some pretty things, and there’s lots of interesting things to know about them.

Calcite

• CaCO3
• Makes up shells of marine animals, constituent of limestone
• Single crystals can show birefringence where you see double looking through them (you can sort of see it in the picture of the flat crystal)
• This particular piece is interesting because it shows twinning. This is a structural feature where multiple crystals grow along the same planes/through each other so you get these beautiful symmetrical patterns. Both sides are totally identical.

Vanadinite

• As the name suggests, has vanadium
• Also comes in a more brilliant red!

Corundum

• Aluminum oxide, aka ruby or sapphire depending on color
• Second hardest mineral after diamond
• Comes in lots of colors and can make nice hexagonal crystals
• Sometimes has these cool triangular etching-like marks? You can sort of see them in the picture, it looks like something made by humans, but it’s not

Lepidolite (and bonus tourmaline):

• Lepidolite is a mica containing lithium
• Lepidolite can make for fantastically purple sparkly rocks!
• The tourmaline here is the pink stuff. It comes in many colors (technically “tourmaline” includes more than one mineral)
• My favorite tourmaline is “watermelon” tourmaline, that’s green and pink like a watermelon

Wulfenite (and bonus hemimorphite):

• Wulfenite (PbMoO4) is the tiny yellowish crystals and the reddish squares.
• Hemimorphite gets its name (“half-shape”) because each end of the crystal can be a different shape. This is kind of unusual.

Malachite

• Copper mineral
• Often found with azurite, a very very blue mineral

Neptunite

• Neptunite’s the shiny black stuff.
• Honestly, I just like the name. It apparently gets its name because it’s often associated with aegirine, and somebody decided to make rocks-named-after-gods-of-the-sea a thing
• The white stuff around it is probably natrolite, which is a zeolite (a group of porous minerals with lots of uses)
• I really wanted one with benitoite, but somebody else got the best one when I wasn’t looking 😦 Benitoite has pretty blue triangular crystals and is fairly rare. Next time…

Pyromorphite

• So green! Also can be brown, orange, grey or white
• Lead chlorophosphate.
• Belongs to the apatite group. Apatite comes from “apate,” meaning deceit. These minerals come in all kinds of colors and are easy to confuse for many other things.

So there’s some fun rocks for you! I also have a bunch of fossils and a ton of cool mystery rocks given to me as gifts. I will have to get them out and take nice pictures of them in the future…