How is it made

 The accents you see are crystals. The analogue of  how frost grows on glass comes to mind, but this is grown with heat.

The art of throwing on the wheel, is not for the fate of heart.  A lot of failures. Just like riding a bike. You have to take  a couple spills before you enjoy the ride.

The first firing is called bisque. After bisque firing, the pot is not so fragile and is easier to handle without breakage.  I fire to cone 04.

Different Frits (ceramic glass) melt at different temperatures which create different looking crystals.  

 Unfortunately for the potter, these materials have become very popular in the modern world. Does lithium, cobalt, nickel ring a bell. These are but a few minerals commonly  used. They are very expensive and sometimes hard to get. Luckily a little goes a long way. 

Before a new glaze color is put on a hand thrown  finish piece, it must be tested. Hence, the test pot. One in ten are successful. Most glazes need retesting until you get it  just right. This takes time and patience. 

This is one of  the mundane critical points of this posses. The two surfaces of the bottom of the pot and pedestal  ring must fit perfectly. If you don't take the time to do this properly, you   will find that molten glaze has made its  way in.  Bonding  the ring and pot together forever.

I use a blender with a rheostat to mix my glaze. This confederation mixes the glaze well with control. Glaze application thickness is also a consideration. Different glaze thicknesses produce different effects.  

Care should be taken in this endeavor. Pots expand and then shrink as much as 15%. You don't want two pots stuck together or kiss the top or side of the kiln. Done that, been there.

Program the kiln controller for the type, size, color of  a crystal. Yes, temperature has a big influence on all three parameters. If you think about it, it's like painting with heat.

After hours , throwing , trimming,  mixing glaze, testing glaze, applying glaze, firing for sixteen hour, letting cool  for fifteen hours. It's time to open the kiln.  

To separate the pedestal ring from the bottom of the pot. Focus the torch at the pedestal. The heat will cause the weak point to fracture though expansion . Hopefully  you will hear a distinct "ping"  sound. Then tap lightly with a small hammer on the tray.  The pedestal and tray should fall away.