This listing is for a rough slab of Marcasite, 100% natural. It can be used for lapidary to make cabochons or as a display specimen.

Details:

• mineral: Marcasite
• color: blue, yellow, silver, gray, brown
• dimensions: approx 6.5 × 4.5 inches
• thickness: approx 1/4 inch
• weight: 284.73 g

The measurements provided are at the widest part and are close approximations.  The piece(s) shown in the pictures is what will be shipped to you.

Some pictures are taken with the stone wet while others are dry.  These are rough, not polished pieces.

Marcasite is a natural iron sulfide mineral (FeS₂) with an orthorhombic crystal structure, a pale brassy-yellow to silvery metallic luster, and high brittleness.

Key Details on Marcasite Plumes and Slabs

Geological Form: Marcasite (an iron sulfide mineral) forms metallic, brass-yellow, or silvery inclusions and fern-like, feathery, or smoky plume patterns trapped inside natural agate or chalcedony, particularly material originating from Indonesia.
Rough Slabs for Lapidary: Lapidary shops and independent sellers offer uncut or unpolished rough slabs featuring these metallic inclusions, which allow makers to map out cabochons, pendants, or display pieces.

Key Facts About Indonesian Marcasite and Pyrite Agates

Chemical Composition: Marcasite and pyrite are polymorphs, meaning they are chemically identical (FeS₂) but form differently. Pyrite has a cubic crystal structure, while marcasite has an orthorhombic (bladed, feathery, or spear-like) structure.
Indonesian Geological Origin: Material from regions like West Java and Sumatra features metallic iron-sulfide inclusions (sometimes replacing organic material like coral or embedded as feathers and plumes) suspended within a colorful chalcedony or agate matrix.
Trade Naming: While sellers frequently market these pieces interchangeably as "marcasite agate" or "pyrite agate," they can contain a mix of both iron sulfide forms or predominantly pyrite/marcasite locked inside the quartz/chalcedony host

This is what Ondrea from WA had to say about our gemstone rough: Exactly as shown in the pictures; carefully packed and shipped quickly; highly recommend this seller!

If you’ll be displaying the slab in your collection, we have easel stands which can be purchased separately.  We have 2″ and 3″ ones available.

  Click here for easel stands

If you have any questions, please contact us.

Thank You

Tim & Tonya Daniels

Safety Advisory (California Proposition 65):

While completely safe to display on a shelf or wear as finished pieces, many raw mineral specimens naturally contain toxic elements, heavy metals, or glass-like structures (such as copper, arsenic, lead, or silica). To ensure your safety, please follow these responsible ownership and lapidary protocols:

• Basic Handling: Always wash your hands immediately after touching raw minerals and never ingest minerals.

• Lapidary Safety: When cutting or drilling, always use specialized safety equipment, including wet-cutting machinery, proper ventilation, and appropriate respirators or masks to avoid inhaling toxic dust or fumes.