From Weapons & Equipment pp 125-126:
Gems and crystals in Glorantha are usually the blood of gods, either living or dead. This crystalized blood can hold magic points and spirits, and it is said that other types of such gems have even more exotic properties. All the gems below do not require attunement unless otherwise noted. Prices are for a stone of size ENC (1/10).
Color Me New: Octagonal gems that shift colors and shades and are used in very high-end jewelry. Wearing a piece of Color Me New (noncumulative) Counts as a showy magical item when CHA is being calculated. Price: 200 L.
Daka Falite: An ember that never goes out, even when pinched. Observed from the spirit realm, it is a small but warm fire. It gives the attuned bearer A +25% to Spirit Combat if they sacrifice regularly to their ancestors and pay due attention to the dead (gamemaster’s discretion whether these conditions are met). Price: 120 L.
Green Cube: This gem, which looks like deep green marble roughly 2 centimeters per side, is used in sacred Ernaldan rites. It is identified chiefly by shaking it, to determine that there is something inside. When held by someone attuned to it (see page 122), it prevents knockback from moving the owner, although it does not mean they cannot fall. If broken, whatever is inside the gem comes out. The gamemaster should determine what this is by
rolling a D100. On a result of 01 it produces a protective Axe Daughter who swears herself to the nearest Ernaldan, friend or foe, for a year’s service. On a roll of 21–00 it is another gem from this or any other gem list but can also be a handful of grain of a local variety. Price: 350 L.
Lhankor Mhy’s Mark: A grey-black stone as light as charcoal. It must be used by someone who has Read/Write (script) of 01%+. When rubbed lightly over a written surface and then a plain surface, it translates the marks made on the first onto the second, in the preferred language and script of the writer. This can be used to copy a script within the same language. 1/10 ENC covers around two pages of script. Price: 50 L.
Lodestone: These exceedingly rare magical stones reliably point in a particular direction, usually determined when they are found. They are generally shaped or marked to make that direction evident. Those sold by dwarves are made of iron and point towards the remnants of the Magnetic Mountain on Jrustela. Price: —
Mostali Viewplate: A plate of crystal that is often secured into a scrying device. Looking through it gives an effect equivalent to Farsee 2. The gem has 1 armor point and 3 hit points. If attached to armor, the gem always takes 1D6 damage when that hit location is struck (roll 1D6, subtract armor, and apply the rest to hit points). It does not regenerate. Price: 150 L.
Sunstone: Sunstone, also known as Yelmalio’s Toe, glows as a candle, but must be worn openly. As with enchanted gold, when used as a focus of a light-based spell, it doubles the radius illuminated. However, if the stone is ever hidden, such as to allow an adventurer to sneak around, the stone dies, leaving a yellow rock that resembles sulfur. The gem may be left with others temporarily without it fading. Price: 50 L.
Threedot: Three black spheres which cling to each other, but to nothing else, even other threedot stones. They always pull, if weakly, towards the point that is central to the other two and are usually used for wayfinding. Price: 70 L.
Trail Stones: Gems of various colors formed when Movement gods were wounded and staggered away. The gems always crawl away from miners, but when attuned (see the section on power-storing crystals in the RuneQuest Gamemaster Sourcebook) allow +1 to MOV and +5% to the owner’s Agility skills category modifier. Price: 500 L.
Vengeance Black: A lumpy black ore with golden strands within it. An oath sworn on Vengeance Black attunes the owner and causes the gold to glow and the black to begin devouring it. The gold will be gone by the next Freezeday of Death Week, but until it is, any skill rolls for actions directly towards fulfilling that oath by owner (gamemaster discretion) have a +10% bonus which may be stacked with inspirations from Passions or Runes. Price: 250 L.