When found a it appears to be an ordinary class pall about 2 inches in diameter.  1 or 2 can appear in any given instance. 

Zorcon used these in traps so likely these will be discovered if a trap is detected and disarmed successfully. They can of course be found other places. The traps usually consisted of a pressure pad on the floor that opened a trap door on the ceiling above the ball would drop out and shatter on impact with the floor releasing the effect. The ball doesn't nee to shatter any Impact that caused a crack or break of any kind will release the spell trapped with in. 

When the Orb Cracks via being thrown dropped, stepped on hard enough. The Orb is very fragile and gets a Strength Saving through vs Breaking DC 17 + strength bonus of the Person hurling it. So usually they will break with minimal effort. When it break it releases the spell inside which is random and up to the DM if being used in a trap. However if being used by a PC the spell effect is completely randomized. Percentile Roll See the Chart  Below. 

1-8 hypnotic Pattern  9-15 Tasha's HIdeous Laughter (Every Creature within 20 Meters)  16-26 Evard's Black Tentacles 27-33 An Illusion of  A Tap Dancing Sahuagin Appears and proceeds to tell the Thrower of the Ball Knock knock jokes for all eternity or until dispelled. 34- 45  Wall of Stone 10' Diameter around target creature 46- 57 Teleport all Creatures within 10 meters of explosion (random direction including up and down 5d12 Miles )  48-66 Web 66-77 Laughter Echoes from no where and follows thrower for 1d10 hours where ever he/she goes it is deafening.  77-88 Otto's Irresistible Dance Every Creature within 10meters 88-95 Feeble Mind (All creatures within 10 Meters)  96-100 Firestorm

DMs Are free to make there own lists but the effect is more fun when Randomized (Think Wand of Wonder)