Terbium Element Number 65 Tb 

 Terbium is a yet another silvery, malleable rare earth metal, and like all rare earth metals, is not found in nature in pure elemental form. Terbium has limited uses, but like most rare earth elements Terbium's uses are specialized. Terbium occurs in monazite, xenotime, gadolinite, and bastnasite and  is difficult to extract from these minerals and purify.

Terbium has 2 allotropes, or variations. The allotropes of Terbium have a transition temperature of about 2352F. Terbium Is mono-isotopic which means this element has only 1 stable isotope. Terbium also has 36 artificial radioisotopes.

Terbium Oxide is a compound with green fluorescence and is used in CRT TV tubes, fluorescent lights, and trichromatic lighting. The lighting application is Terbium's biggest use. Terbium is also used in solid state devices, and other electronics applications.

Because Terbium has a magnetostrictive trait, it is alloyed with Iron and Dysprosium to form a special compound. The compound TerFenol-D was developed by Navel Ordnance Laboratory. The use of this alloy in sonar, ultrasonic transducers and sound bugs. Sound bugs are devices which can turn a flat surface into speakers, such as storefront glass and other resonate flat surfaces.

Terbium is somewhat expensive and element samples of 10 grams can cost up to 120USD. I was lucky to find a lab liquidator and score a 25 gram sample

 Nice chunks of pure Terbium with cleaned surfaces. each piece weighs about 7 grams an would have been  used for research.

 Tb  65  Lanthanide  AW:158.92535  D:7.90  MP:2394  BP:5923

Dysprosium Element Number 66 Dy 

 A small chunk of Dysprosium with cast surfaces and also a shear break surface.

Dy  66 Lanthanide  AW:162.5  D:8.540  MP:2565  BP:4653 

Dysprosium is a rare earth metal and has many traits in common with other RE metals. It is a soft malleable silvery metal. Dysprosium is found in monazite, xenotime, and most other RE metal bearing minerals, Dysprosium is also found in polycrase which is a Uranium bearing radioactive mineral. Dysprosium has a high abundance in the heavy Lanthanide series but because of its uses in certain technology Dysprosium is expected to become super scarce.

Dysprosium can be used to enhance NIB magnets in ratios of approx 6%.  TerFenol-D is a Dysprosium alloy used in sonar devices and special speakers. Dysprosium can be used in control rods for nuclear reactors, and also in dosimeters to gauge ion radiation exposure.

Special lighting applications use Dysprosium and compounds. Vanadium and Dysprosium can be used in lasers and lighting. High intensity lights can be made with Dysprosium Bromide, and Dysprosium Iodide.

Less than one year ago, I had the opportunity to purchase Dysprosium ingots for a fifth of the current costs. I am happy with my 5 gram sample. If I was going to invest in a rare earth metal, I would choose Dysprosium, for its important uses and rising costs.

Here is yet another 5.5 gram piece of Dysprosium. This piece has a bit of oxide forming.