Rare and Unusual (and mostly still unknown) Gemstones of Indonesia
with the jewelry of Irwan Williams-Holmes.

Most people who live here know that Indonesia is one of the biggest producers of South Sea Pearls in the world.  Some people also know (or have heard) that Indonesia (Kalimantan, formerly Borneo) is also an important diamond producer.  But few people know that Indonesia also produces some of the most beautiful semi-precious stones in the world, and many are only found in Indonesia.

Fossilized Coral (the “Flower Stone”)

Agatized fossilized coral (or more commonly “fossilized coral”) has so far only been found in Indonesia.  The opaque material (usually with stronger colors) is found mostly in Java.  The translucent material (usually with softer colors and smaller “flowers”) is found in Sumatra. The remarkable thing about this semi-precious gem is, of course, that the ends of the fossilized coral stalks look exactly like flowers and some of the best stones look precisely like bouquets or even gardens. The colors range from white through cream to yellows, oranges and all sorts of reds (even pink); browns; black and we’ve even had some green material, although it wasn’t very attractive.  There has even been some lavender material – which seems, come to think of it, to cover most all colors.


Chrysacolla is a blue-green semi-precious stone that sometimes resembles turquoise.  Before China discovered and marketed its tons of turquoise, this popular gem (especially Persian) was very expensive and chrysacolla (discovered recently in Sulawesi) was often used as a substitute.  Now good chrysacolla is more expensive, and it is much harder than turquoise so it doesn’t discolor or break easily.  The good, even-color, translucent stones can fetch up to $60 per carat on the international market, but I like to use those stones with a mix of the blue and black as the contrast is so beautiful.

The Famous Pancawarna Gems of Java

Pancawarna (sanskrit) means “multicolored” and is a term that has been used for decades perhaps centuries to refer to the multicolored agates and jaspers of Indonesia, more particularly for stones from Java. Panca, of course, means five and it is the stones with five colors that command the high prices.  If you count black and white as colors, these rare and valuable stones could contain five, six or even seven colors. The pancawarna gems often have a lot of black and sometimes with white so the contrast in colors is very strong.  This contrast is one of its special features. The material is very hard (6.5 to 7.0 on the Mohs scale – almost as hard as jade) and takes a good polish.  There are often wonderful color patterns resembling abstract paintings, and very rarely what seems to be a picture – flowers, leaves, landscapes and even animals or human forms.  These stones can be very expensive and are highly sought after in the local market. “Drusy” is the term for a stone that has small crystals on the outer skin of the natural rock.  In the past lapidarists ground it off but some years ago they began to realize that it was also very beautiful, so they began cutting drusy stones. There are drusy stones in all countries of the world.  Russia has a beautiful green garnet drusy; drusy agates, white, yellow, orange and particularly black are found all over the world and now used frequently in the jewelry trade; but Indonesia has a magnificent fire-engine-red drusy jasper that, as far as we know, doesn’t exist anywhere outside Indonesia.

The “Allah Gemstones”

Geologically and Gemologically these gemstones are in the chalcedony or agate family, but the inclusians very occasionally spell out the Arabic word, Allah. They  are usually a translucent white-to-grey, but occasionally can be a carnelian red to brown. The “writing” can be white, reddish-brown or even a dark sepia color. The “Allah Gems” are extremely rare—you may have to split open 10,000 pieces of agate rough to get one, and it’s not sure it will be a good one (the writing can be more accurate or less, and easy to read or not so easy to read). As the world of Indonesian semi-precious stones is so new, we find new and remarkable gems all the time.  Our most recent find is a flame agate that is so realistic you can feel the heat.


Irwan Williams-Holmes is an American jewelry designer living in Indonesia for 40 years.  He now uses Indonesian gems exclusively in his design work and has exhibited the stones and jewelry in Dubai, Tokyo, Munich, Tucson (Arizona, USA), Paris (where he won first prize for design), Innsbruck (Austria) and in Jakarta.

(Jewels by Irwan can be contacted at Jl. Ciputat Raya 50, tel: 749 2850, email: dmulia@cbn.net.id)



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