Rough Nobby vs. Seam Opal Differences | Black Opal Direct
Oct 10, 2012 · Rough Seam Opal. Rough seam opal is called so because it is flat and is formed by silica-rich water running through seams and cracks in the earth. It can be thin or thick, depending on the size of the fissure, and can color but not always.
Nobbies & Seam: Opal Forms | OpalWords @ Lightning Ridge
Lightning Ridge opal comes in two common formations: nobbies and seam opal.
Beginner’s Guide: What Are the Different Types of Opal?
Mar 13, 2019 · Opal is comprised of tiny silica spheres, formed when silica-rich water seeps into deep cracks and voids in the Earth’s crust. It is separated into two groups, common opal (also known as potch) and precious opal (also known as noble opal).
How To Value Opal - The 10 Factors - Opal Auctions
Oct 15, 2020 · Opals are grouped in 9 sub categories N1 to N9 with N1 the darkest opal and N9 the lightest. Black opals are generally the most valuable and have a body tone of N1 to N4. Opals with N5 to N6 considered a semi black or dark …
Opal Gems: Value, Price, and Jewelry Information - IGS
Seam opal: thin to thick seams of white or black opal in sandstone matrix. Also known as sandstone opal. Large stones are very rare in this material. Notable Australian Sources. Major finds of Australian opal are best known from specific localities, including the following:
Geological Classification - Opal Academy
Jul 24, 2019 · Opal is often described by its mode of formation within the geological environment and consequently terms such as seam opal, “nobby” or nodule opal, nut opal, boulder opal, and pipe opal, are terms that have been widely used to describe opal.
Opal Description - GIA
Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback.” The showers soaked deep into ancient underground rock, carrying dissolved silica (a compound of silicon and oxygen) downward.
Sandy Seam Opal - Black Opal Direct
Sep 24, 2024 · In this video, I’m working with a rough piece of sandy seam opal from Lightning Ridge, full of sand and inclusions. It doesn’t look promising, but I’m determined to give it a go. The goal is to cut through the rough exterior and hopefully reveal a gem hiding inside.
A NEW UNDERSTANDING OF HOW SEAM OPAL IS MADE IN …
Jun 11, 2024 · Gerard Faber's paper on the formation of seam opal in nature is quite detailed and provides an in-depth understanding of the geological and chemical processes involved. The journey from Gondwana's breakup, the role of diatoms, the formation of the Eromanga Sea, and the conditions required for opal formation are explain
Seam Crystal Opal - Black Opal Direct
Oct 12, 2021 · To find a gorgeous piece of crisp and clear Crystal Opal from Seam Country in Lightning Ridge is quite rare, they are usually found to be quite milky or white — so I am super excited to see what emerges.