*Amethyst Stalactite from Uruguay
*Sterling setting with 14kt white gold prong settings, sterling beads and findings
*Brazilian and African amethyst, 2.5 mm round faceted amethysts
*Earrings have sterling leverbacks
*Necklace is signed, numbered, dated

Length: 16.5" - 21.5" (42 cm - 54 cm) Shown on model at shortest length
Centerpiece: 2" (5 cm) diameter
Weight: 4.2 oz (119 gm)

Earring drop length: 1.25" (3 cm)
Earring weight:  2.7 gm ea (a nickel weighs about 5 gm)

Item #567 - SOLD

Amethyst Stalactite Necklace

Amethyst Stalactite Necklace
Amethyst Stalactite Necklace Detail
Amethyst Stalactite Necklace on model
Amethyst Stalactite Earrings
Amethyst Stalactite Necklace
Hover to zoom, Click to expand

This big bright amethyst stalactite is from Uruguay. Stalactites, which grow downward from the ceiling of a cave, can be distinguished from stalagmites which grow upward because generally the stalactite will have a single center. When the droplets fall to the stalagmite, they may land in different spots resulting in multiple centers. Or so I've been told. Checking this theory, I found that stalactites and stalagmites are a type of speleothem called a dripstone which is typically composed of calcium carbonate though it may be formed from other minerals. One wiki article mentions that speleothems may occur in lava tubes formed by the cooling of the lava and not by drips of mineral laden solution. Amethyst vugs occur in basaltic magma, so... The wiki article on lavacicles (don't you love the name?) describes how the stalactites are thought to form by lava deposition as it splashes. However our lovely crystal is not lava. Is the center a lavacicle that amethyst crystals grew on? The white center looks more like calcium carbonate than lava to my uneducated eye. What minerals produced the rings of color in the center? Brad L. Cross says, "These amethyst 'stalactites' are formed when amethyst crystals grow as a coating over agate or calcite tubes that have occasionally grown inside the geode during formation." He goes on to note that perhaps 1 in 10,000 of these rare stalactites are nice enough to be a "mineral collector's fantasy."

You've probably seen the huge amethyst geodes from Brazil. I used to have a link here to a fascinating paper entitled Genesis of amethyst geodes in basaltic rocks of the Serra Geral Formation (Ametista do Sul, Rio Grande do Sul, Brazil): a fluid inclusion, REE, oxygen, carbon, and Sr isotope study on basalt, quartz, and calcite. (Unfortunately the paper is now gone, perhaps you can find it somewhere on-line.) The study adds many interesting details to the basic theory that cavities formed in basaltic magma, fluids filled the cavities and eventually gorgeous amethyst crystals developed. They mention in passing that "rarely agate stalactites occur in the cavities." In fact, in cruising the 'net you can find photos of typical amethyst geodes sliced off at the bottom and showing a crystal stalactite much like this one inside. The center of these crystals usually appears to be agatized. The article goes on to mention that geode formation in Uruguay (where this stalactite grew) may differ from the processes which resulted in the Brazilian geodes and may instead be related to fusion or dissolution of sandstone xenoliths. Great. It always seems the more we learn the less we know for sure!

High time to throw up our hands with a "Whatever!" Please order this lovely specimen and perhaps start your own geological journey.