Oregon Sunstone Grading
by Jeff R. Graham - copyright 2007

Here is a link to my Gemstone Grading page
Common Sense Gemstone Grading by Jeff R. Graham

There is no current grading system for Sunstone. So I have created what I think is a versatile common sense grading system.

Note: There are many types of Feldspar and depending on the location the material may have various colors as well as schiller (suspended color particles of copper usually).

But the term Sunstone is generally reserved for the material found in Oregon, USA.

Sunstone at this point in time is still some what of a novelty gemstone. However because of it's unique properties I believe Sunstone will eventually become a world recognized gemstone.

Note2: All Feldspar is not much over 6 to 6.5 on the Moh's hardness scale and it has 2 distinct cleavages (that are usually not a big issue during cutting). So Sunstone is basically a gemstone that works best in protected settings or in pins and pendants, as well as earrings where the stone(s) will have some protection from hard wear.

Note3: Some of these values and rarity of colors may vary depending on the mining and what is being found.

Note4: It is important to separate schiller material from colored material with little or no schiller. Schiller as it becomes stronger than the "Pale" or "Light" stage starts to block light because of the particles/layers of copper schiller. So basically any Sunstone that has more than a light amount of schiller needs to be facted in a special design and orientation, or the material is carving/cabbing material because it will not facet well, unless faceted using special techniques and designs.

Note5: There is a rarity in most color Sunstone as it gets above 4 carats and clean. I generally price it in the upper range. Above 8 carats is rare, above 12 carats is a collector stone in color.

Sunstone Colors: Red, green, teal, blue, yellow, watermelon, schiller, copper, orange, pink.

There are 3 basic types of Oregon Sunstone
Clear yellow/champagne - This material is the most common and can often be confused with other types in the feldspar group. Some times a slight green tint.
Color with schiller - This is the largest category. Schiller is copper particles (in Oregon material) like grains suspended in the clear/champagne colored material. Schiller (copper particles in Oregon material, generally Hematite in Indian and African material) is usually copper colored and often does have other colors as well as the schiller copper in the same stone. The color/schiller is almost always in layers and spots surrounded by the clear/champagne material. Color with shiller is almost always best as carving material if the schiller is dense (except for the exception of special faceting and designs as noted).
Color - This material is the rarest and there can be a very tiny amount of schiller in this, but the material is basically open with little to no schiller of any type, and can be any color. The color is almost always in layers and spots surrounded by the clear/champagne material.

Colors and Rarity of Oregon Sunstone
Clear yellow/champagne - This material is the most common and the least expensive. Some times a slight green tint.
Copper/pink/orange - This material is pretty common and there is usually some schiller, although material with no schiller that is copper/pink does occur.
Root beer - This color occurs at some mine locations and can be a bit milky. This color also can be caused by red/pink and green colors mixing to cause the root beer color (poor orientation can and often does cause this), or just the root beer color in the stone itself. This is generally not considered valuable.
Bi color, Tri color - Usually watermelon red/green, but can occur in various color combinations. One of the most valuable types.
Red - This color is considered one of the most valuable and it is not a common color.
Green - This color occurs rarely and is a collector color. Often the green is more a teal color.
Blue - Usually a blue/green or teal, some times a Turquoise blue, very rare and a collector color.

Dichroic and Trichroic Sunstone - The dichroic material is not common but around, it is usually pink/orange/copper to green/teal in nature (can have a lot of schiller or almost none it just depends on the individual stone). It displays a definte color change depending on the axis.

Trichroic is rare and usually involves pink/orange/copper to teal/green/blue. The effect of the dichroic or trichroic material is that the colors occur on different axis's and the color(s) appear to move around. Great care must be taken in orientation of these types to prevent mixing the colors incorrectly and creating an ugly finished color. The effect of the various colors moving and mixing is called pleochroism. I generally consider this prime carving material if it contains schiller.

Champagne
Pale (almost colorless to 15% tone) - Pale to light yellow/champagne. Some times a slight green tint.
Comments - This material actually can be valuable, especially when cut into a large unusual designs.

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Schiller - This material is basically all carving, not faceting with the exception of light schiller which can be faceted if orientated and handled correctly.
Light (15% tone to 30%) - Light with a copper/pink tint. Can be color with the schiller.
Comments - This material actually is valuable and I sell it faceted quite well, especially when cut/carved into a large spectacular design.

Medium (45% tone to 65%) - Schiller with a medium copper/pink or other color (red, green, bi color).
Comments - This material is valuable and not always easy to acquire. This material is cabbing and carving grade, particularly the multiple colored schiller.

Medium/Dark (65% tone to 85%) - This is what I would consider to be the top color range in carving. Very intense green/copper/red color with schiller but still light enough to distinguish the carving and light patterns in the design of the finished stone.

Note the red/copper/orange to green and teal color range of this material. It is gorgous, but becuase of the schiller it generally would not make a good faceted stone. There are exceptions.

Comments - This material is valuable and difficult to find. I cut/carve this material in whatever size the stones require.

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Bi Color - No or very little schiller.
Light (15% tone to 30%) - Light green/teal/blue with light pink/red center.
Comments - This material is valuable and I sell it faceted quite well, especially when cut into a unique design. It also carves very well as you can see in the picture.

Medium (45% tone to 65%) - Medium green/teal/blue with red center.
Comments - This material is valuable and not always easy to acquire. I cut this material in what ever the rough will cut and typically use unique designs.

Medium/Dark (65% tone to 85%) - This is what I would consider to be the top color range in Sunstone. Very intense green/teal/blue/red color but still light enough to distinguish the facet and light patterns in the design of the finished stone.
Comments - This material is valuable and difficult to find. I cut in unique designs.

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Green - No or very little schiller.
Light (15% tone to 30%) - Light green/teal.
Comments - This material is valuable and I sell it faceted quite well, especially when cut into a large stone.

Medium (45% tone to 65%) - Green/teal.
Comments - This material is valuable and not easy to acquire. I cut this material in what ever the rough requires typically use unique designs

Medium/Dark (65% tone to 85%) - This is what I would consider to be the top color range in Green/teal. Very intense green color but still light enough to distinguish the facet and light patterns in the design of the finished stone.
Comments - This material is valuable and difficult to find. I cut this material in the smaller to medium size ranges and typically use unique designs

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Red - No or very little schiller.
Light (15% tone to 30%) - Light red, some times with an copper/pink tint.
Comments - This material is valuable and I sell it faceted quite well, especially when cut into a large stone.

Medium (45% tone to 65%) - Red, some times with a slight copper/pink.
Comments - This material is valuable and not always easy to acquire. I cut this material any way I can get it.

Medium/Dark (65% tone to 85%) - This is what I would consider to be the top color range in red. Very intense
red color but still light enough to distinguish the facet and light patterns in the design of the finished stone.
Comments - This material is valuable and difficult to find. I cut this material in the smaller to medium size ranges and typically use unique designs.

Feldspar Index

E-mail to inquire or order: jeff@faceters.com or jeff@cabbers.com