Gabbro Gemstone Beads

Frequently asked questions

• Is gabbro the same as Indigo Gabbro or Mystic Merlinite?

  Yes — all three names refer to the same Madagascan material. "Gabbro" is the geological / mineralogical name for the coarse-grained intrusive igneous rock composed of plagioclase feldspar and pyroxene. "Indigo Gabbro" is the most common bead-trade label, referencing the dark base with subtle cool-tone shift. "Mystic Merlinite" is a marketing name introduced into the trade for the same stone. Note that "Merlinite" without the "Mystic" prefix is a different stone — a dendritic agate from New Mexico — so the two names are easy to confuse but refer to unrelated material.
• Where does gabbro come from?

  The gabbro reaching the bead trade is sourced principally from Madagascar. Gabbro as a rock type occurs worldwide — it is one of the most common rocks in the lower oceanic crust — but the commercial bead material with the recognizable dark base and lighter mottling is consistently Madagascan. Dakota's gabbro is from this source.
• What is gabbro made of?

  Gabbro is an igneous rock composed primarily of plagioclase feldspar and pyroxene, with magnetite and varying accessory minerals — olivine, biotite, chlorite, serpentine, and others depending on the deposit. The lighter gray-white patches in a polished bead are the plagioclase; the dark matrix is the pyroxene and finer mineral grains. It is the plutonic (slow-cooled, coarse-grained) equivalent of basalt.
• How durable is gabbro for daily wear?

  Mohs ~6. Durable enough for any jewelry application including necklaces, bracelets, and earrings. Standard care: wipe with a soft cloth and mild soap. Because gabbro is sold natural with no dye or stabilization, there is no fade risk and no special cleaning concerns.
• What's the difference between gabbro and basalt?

  Same chemistry, different cooling history. Gabbro is intrusive — it cools slowly deep beneath the surface, producing coarse-grained mineral crystals visible to the eye (the mottled look of a polished bead). Basalt is extrusive — it cools rapidly at the surface in lava flows, producing fine-grained dark rock with crystals too small to see without magnification. The mottled appearance designers buy gabbro for is a direct consequence of the slow underground cooling.