These are great to show the density of tungsten in a smooth, comfortable way. The 1.5" sphere weighs in at over a pound (nearly half a kilogram) and the 1" is over 5 ounces (147g) Here's what they look like next to our kilo cube:
They are shockingly heavy for their size! You can really feel the weight pressing against your hand. Keep it in a safe place away from children and pets and be aware of its potential energy.
Tungsten has the highest melting point of any element. In fact, you can't easily build a container to melt it. You have to resort to expensive powder compression methods to form it. Tungsten is an extremely rare element (only 100 parts per billion in the earth's crust).