The base value of gems found in a treasure can be determined in whole or by lots of 5 or 10 stones by rolling percentile dice:
Value of a gem depends upon its type, quality and weight. A huge semiprecious stone - carnelian, for example - is worth as much as an average gem stone, quality being equal. Size may vary from stone to stone, a 50 g.p. ornamental stone being of above average size, while a 50 g.p. gem stone would most likely be very small.
Increase Or Decrease Of Worth Beyond Base Value: If you do not place specific value on each gem in a treasure, showing rather the base value of each gem instead, then variation in the worth of each stone should be allowed. This variation will generally result in some increase, although there is a chance for decreasing value as well (see below). To find if a gem increases in value, roll a d10 for each stone, and consult the table below:
* Stones above 5,000 gold piece value progress as follows: 10,000 g.p., 25,000 g.p., 50,000 g.p., 100,000 g.p., 250,000 g.p., 500,000 g.p., and 1,000,000 g.p. - the absolute maximum. No stone may increase beyond 7 places from its initial base value.
** Stones below 10 gold piece value are: 5 g.p., 1 g.p., 10 s.p., 5 s.p., and 1 s.p.. No stone may decrease beyond 5 places from its initial base value.
When base value only is known, use the table above, and roll for each stone. Stones for which a 1 or a 0 is rolled must be diced for again on the table, but all others are excluded from such rolls. If large numbers of stones are in question, it is suggested that they be diced for in groups in order to make the process less time-consuming.
Key to Gem Properties
The base value of jewelry is determined by percentile dice roll, just as with gems:
Once jewelry’s base value is determined, each piece should be checked for workmanship and design by rolling a 10-sided die. Each “1” rolled indicates the piece of jewelry in question is of exceptional value and thus either goes to the highest possible value in its class or to the next higher class (where its base value is re-determined and its workmanship and design are again checked). Any piece of jewelry set with gems must also be checked for the possibility of an exceptional stone in the setting. Any score of “1” on an 8-sided die indicates that the value of the piece of jewelry increases by 5,000 gold pieces, and these exceptional pieces are further checked by rolling a 6-sided die, each successive “1” doubling the increase, i.e., 10,000 g.p., 20,000 g.p., 40,000 g.p., 80,000 g.p., to a maximum of 640,000 gold pieces.
The Dungeon Master can, of course, name what each piece of jewelry is (bracelet, brooch, crown, earrings, necklace, pendant, ring, tiara, etc.), giving its substance and the number and value of its stones.
Note regarding the magical properties of gems, herbs, et. al.: Regardless of what qualities gems, herbs, and other substances are purported to possess, the mere possession of a score of a type of gem or a bale of some herb will convey absolutely no benefit of magical nature to the character concerned. These special qualities are given herein merely as information for Dungeon Master use in devising special formulae for potions, inks, etc. The information might also prove useful in other ways, particularly with regard to description of magic items, laboratories, and so on. Under no circumstances should you allow some player to convince you to the contrary!