If there was a number other than million that started with "m" I would have been clever and used it here, but here are nine magic mineral things. Use them - I command it!
1. A copper-colored crystal, about 4 inches long, that vibrates in the presence of earth elemental creatures. The vibrations begin when you are within 100' x the Hit Dice of the creature and intensify as you get closer. When you are within 1' x the Hit Dice of the creature the crystal explodes, sending shards in a 10' radius and inflicting 1d4 points of damage per person minus their armor bonus.
2. A small, bluish gemstone - maybe 1 inch in diameter. When affixed to the skin of a person's head, it exudes a soft glow in a 10 foot radius and increases the subject's intelligence by 1 point (no maximum). Unfortunately, it also permanently robs them of 1d3 points of constitution. One might stud their head with these strange gems, gaining even godlike intelligence at the cost of their health and possibly life. Once affixed, it cannot be removed without boring into the person's skull. Keep in mind - raising your character's intelligence to godlike levels is probably useless if there's no reward for having a godlike intelligence score - see Gods, Demigods & Heroes or Legends and Lore for more.
3. This leather bag of gravel looks, at first blush, to be completely useless. However, it releases a slow stream of gravel as the bearer walks - essentially leaving a trail to allow them to find their way out of whatever nonsense they have walked into. Of course, it also leaves a trail for others to follow. The gravel never runs out completely.
4. This tiny jewel is bright green in color and seems to give off an electric charge when touched. If stuck in one's nose, it gives them the olfactory senses of a wolf. If placed in the ear, it gives one of the auditory abilities of an elf. If placed in the eye, it hurts. If swallowed, it takes about one week to move through the digestive system. The jewel is actually an alien artifact that was miniaturized when it passed into our dimension. If the jewel is ever in the presence of an enlargement spell, it returns to its full, normal size as a geodesic domed vessel 40 feet in diameter carrying a crew of 30 misshapen avian quadrupeds that look vaguely like a cross between buzzards and orangutans. The creatures, called bangisps, are captained by a suave gentleman called Ufixya who fights as a 7th level fighter.
| Bangisp: HD 2; AC 6 ; Atk 1 slam (1d4+1) or 1 weapon; Move 12; Save 16; CL/XP 3/60; Special: Sixth sense - allows them to re-roll all saving throws and improves their armor class by +2 (already included). Soldiers wear plasteel suits (treat as chainmail, but heavy as leather) and carry electro-rods that can deliver 2 dice shocks in melee combat or 1 dice shocks in ranged combat with a max range of 20 feet.
5. This piece of masonry looks like a dull red brick. When tapped forcefully against the floor, it quickly multiplies into a brick wall up to 30 feet long and high. The wall lasts for 1 hour (no more, no less) and is in all respects a normal brick wall (consider it about half as strong as a wall of stone).
6. This large medallion appears to be made of a silvery metal as strong as steel. It is stamped with a symbol consisting of four interlocking circles. When worn as a pectoral, it gives one the fighting abilities of six men (i.e. level 6 fighting-man), but only while rescuing a maiden.
7. This small hammer is highly prized by the dwarves. Lost for several millennia, it has the ability to create a vein of metal (user's choice) when tapped against stone. The vein runs for 1 mile and must be refined to be of any use. The vein creates as triple strength earthquake on either end when created.
8. This gray cloak, when thrown over the head of a crouching person, not only makes them look like a boulder, but is also as strong as stone.
9. This pebble looks like a tiny river stone. When tossed into a room, it creates a bubble of force that shoves people and objects in the room violently against the walls (1d6 points of damage) - probably only enough to destroy fragile materials and objects. If a person holding the pebble is knocked around a bit, or falls to the ground, there is a 3 in 6 chance the pebble "goes off" inadvertantly.