Moss Agate
Moss agate is a natural variety of chalcedony (microcrystalline quartz, SiO₂): a colorless to white, translucent stone containing green, moss-like inclusions of minerals such as chlorite or hornblende, sometimes with brown to black dendrites of iron or manganese oxides. Despite the name it is usually not banded like a true agate. Mindat lists tree agate and medfordite as synonyms; "mocha stone" is an older name used inconsistently by vendors.
Products made with this material
Showing 1 of 1 products
Full material guide
What the material is, where it comes from or how it is made, identification and care, from the cited sources.
Properties
| Material type | Natural chalcedony with mineral inclusions (dendritic agate; variety of quartz) |
| Chemical formula | SiO₂ |
| Inclusions | Green chlorite or hornblende (amphibole) in moss-like patterns; sometimes iron or manganese oxide dendrites |
| Color | Colorless to white with green veins or patches; can also show brown and red patterns |
| Crystal system | Trigonal (microcrystalline) |
| Mohs hardness | 6.5 to 7 |
| Specific gravity | 2.58 to 2.64 |
| Refractive index | 1.530 to 1.540 |
| Transparency | Translucent |
Origins & sources
Moss agate occurs as fillings in fissures or as pebbles. The IGS names India, Scotland and the northwestern United States as sources; it also mentions deposits in California, Colorado, Montana and Wyoming, a few mines in Canada and the UK, and India's reputation for fine material. Mocha in Yemen is an ancient source. Mindat lists more than 120 localities worldwide, including the Deccan Traps of India.
Identification
Moss agate is recognized by plant-like inclusions suspended in a milky, translucent body; plume agate shows feather-like forms and dendritic agate tree-like branching instead. When the iron in the green chlorite or hornblende oxidizes, the inclusions turn brown or red, and some stones show all three colors. Vendors use "mocha stone" inconsistently, for all moss agate or only for red and brown material, so judge the actual stone. Dyeing is a common enhancement for agates in general and should be disclosed.
Care
Light and water do not affect moss agate, but some household chemicals may harm it. Clean it with a soft brush or cloth and mild soapy water, including the back of the stone, and avoid mechanical cleaning systems, which can shatter some inclusions and fracture the stone. Thin cabochon edges can chip, so protect them from knocks.
History
According to the IGS, chalcedonies have been used for jewelry, amulets and carvings for almost three thousand years, but lore specific to moss agate only goes back to the 18th century. Its association with Mocha in Yemen, an ancient source, is why some people still call it "mocha stone".
Cultural meanings
The IGS reports that the symbolism of moss agate is associated with a healthy ecosystem and cosmic balance, extending from farming to the home and personal relationships; some people consider it a stone of friendship, and some believed that keeping moss agate in the house brings good luck.
Traditional beliefs
Farmers are said to have favored moss agate, perhaps because they believed its plant-like appearance could help their crops grow.
Collected Oct 23, 2026
- Moss Agate: Mineral information, data and localities Mindat.org (Hudson Institute of Mineralogy) · Accessed Oct 23, 2026 OverviewPropertiesOrigins & sources
- Moss Agate gemstone information Gemdat.org · Accessed Oct 23, 2026 OverviewPropertiesOrigins & sourcesIdentification
- Moss Agate Engagement Ring Guide International Gem Society · Accessed Oct 23, 2026 OverviewOrigins & sourcesIdentificationCareHistoryCultural meaningsTraditional beliefs
- Is Moss Agate Expensive? International Gem Society · Accessed Oct 23, 2026 Origins & sourcesIdentification
- Agate Value, Price, and Jewelry Information International Gem Society · Accessed Oct 23, 2026 Origins & sourcesIdentification