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. Treatment, when present on any strand — ask before buying if it isn't specified, though gabbro is consistently natural across the trade.
• 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.