An Important Note on Selecting Colors: Because colors are subjective from individual to individual sometimes it is better to use the base color such as blue rather than a descriptive color such as greenish blue. Say you have a stone that is somewhat greenish blue. You can select greenish blue or bluish as your color in the Gemstone Separator and most of the time you will get a Direct Hit but if you use Blue you may get better results. For many gems, their full range of color hasn't been discovered or reported.

 The Gemstone Separator can be a great help in separating gemstones. Naturally, you'll still have to use your gemological skills and knowledge to make the final call. There are some separations that really need to be made with the microscope. We have tried to help in that area by way of the Magnification field. While every effort has been made to ensure the accuracy of the data and the logic we make no guarantee of same. Be careful with the "subjective" fields (Color, Pleochroism, UV Colors, Magnification and Polish Luster). If you don't get expected results try removing one or more of the "subjective" fields. As always in gemology careful measurements are paramount.

ERRORS: If you find (or suspect) any errors in either the gemstone database or in the search logic please email me at ubwise@comcast.net and we'll work on it as soon as possible. All help is greatly appreciated.

TIP: Enter the fields with measurements before the more subjective fields such as transparency, hardness and polish luster. Start with Color, Optic Character, RI and SG (if available). These fields will quickly narrow the list.

TIP: If you click on the Crystal System column and lose sight of your gemstone list on the left simply hit the Home key. This will return you to the gemstone list.

To start the Gemstone Separator press the Gemstone Separator button on the Gemstone Database page. The Gemstone Separator dialog box will come where you can enter any data you have on your target gemstone. Press the diamond Query button to start a search. Press the Reset button to reset all fields to no value. This will give you a fresh start on a new search.

Note: The convention used for Color is that greenish blue is mostly blue with some green in it. Green-blue has equal amounts of green and blue and is the same as blue-green. Naturally, bluish green is a green color with some blue in it. This is the same for all the colors.

What's New in the Gemstone Separator: The RI and SG Near Hits buffer zones! There are now two sliders at the bottom of the Gemstone Separator window which give you increased flexibility when identifying a gemstone. One slider allows you to enlarge the Near Hits buffer zone from 0% to 2% (1.0% default) for Refractive Index and the other allows you to enlarge the Near Hits buffer zone 0% to 10% (5% default) for Specific Gravity. What this means is that you will get Direct Hits and Near Hits when you have the Show Near Hits box checked. A Direct Hit is a gemstone where ALL the parameters you have entered into the Separator fall within the normal range for the gem. A Near Hit is a gemstone that falls within the percentage shown on the respective slider. RI Near Hits are shown in red text bordered in blue and SG Near Hits are shown in blue text bordered in red. In the screen shot below you can see that the first two gems are Near Hits (Achroite and Actinolite). The third gem (Allanite) is a Direct Hit for RI.

Data Entry Fields:

Color: You should always select a color. Choose the base body color from the drop down list. If the color isn't in the drop down list then the color isn't in the database. With our new Color Near Hits feature you can be assured you will get a Near Hit as long as you get the base color correct. For instance, if you enter bluish green into the Separator Color field but bluish green isn't listed in the database but green is (the base color) then you will get a Color Near Hit. This will show up as green text in the Gemstone result field. Since color is somewhat subjective you shouldn't be as quick to dismiss a Color Near Hit as you might with other Near Hits.

Your first choice should be the basic body color. Use the "ish" colors (yellowish, brownish etc) if you can't decide on a basic body color. One case to consider is Fire Agate. Fire agate has many iridescent colors but the body color is brown. In this case, brown or brownish are the only colors that will provide a match.

Spectral Images: To see an array of all spectral images for a certain color, enter that color in the Color field. Example: You want to see all the red gemstones for which there are spectral images. Enter red in the Color field. On the far right of the screen you will see an odd spectral-type image with the color over it (in this case red). Single-click that image and it will open your red gemstone example file.

Optic Character: Select the Optic Character (SR, ADR, DR, AGG), the Optic Figure (Uniaxial, Biaxial) and/or the Optic Sign (+,-) from the drop down list. If you only know that a gem is DR then pick that. If you know that stone is also Uniaxial then select DR U. If you know the optic sign, as well, that will help to whittle the list down even further. If the optic sign is either "undeterminable" or "without sign" simply omit it.

Refractive Index: Enter your readings for Refractive Index into the RI High and RI Low fields. You can control the range of hits by setting the RI Range Slider (lower left part of the screen) from 0% to 3%. The default setting is 1.5%. What this means is that the RI range will expanded by 1.5%. Example: You enter 1.66 into the High RI field. Since the range is 1.5% you will get Direct Hits for all stones that have 1.66 as a possible RI and Near Hits for all stones that are between 1.661 and 1.6849 (1.66 * 1.015 = 1.6849). It works the same way for Low RI.

RI High/RI Low: If your target stone is DR you will be allowed (but not required) to enter the high RI of your stone (as well as the low RI). Entering both RI readings will help the narrow your search but it isn’t mandatory.

Note: If you enter only one RI it doesn't matter which field you enter it in (RI High or RI Low). If you select SR the second RI field (RI Low, as well as the pleochroism fields) will be unavailable (grayed out).

Over 1.81: Most refractometers don't make readings over 1.81 (OL). If the stone you're working with is over the limits you can enter >1.81 and the Separator will hit all those above 1.81. In fact, you can use either < or > in the RI fields, the SG field and the Hardness field.

Sliders: The RI Range slider lets you adjust the buffer zone for Refractive Index and Specific Gravity. Example: Let's say you have a light blue stone and you see 1.61 in the refractometer. It's a little fuzzy. Could be 1.60 but looks more like 1.61. You enter 1.61 into the Gemstone Separator and hit Query. If you have the Show Near Hits box unchecked or have the RI Range slider set to 0% you will not get a Hit for Aquamarine. Since Aquamarine can go up to 1.60 it's nice to have the buffer that the RI Range slider gives you. Check the Show Near Hits box and move the slider over to 1.5%. Now Gemology Tools will show you all the gems that are within 1.5% of the RI you entered.

Specific Gravity: Enter your reading for Specific Gravity into the SG field. You can control the range of hits by setting the SG Range Slider (lower left part of the screen) from 0% to 10%. The default setting is 5%. What this means is that the SG range will expanded by 5%. Example: You enter 2.55 into the SG field. Since the range is 5% you will get Direct Hits for all stones that have 2.55 as a possible SG and Near Hits for all stones that are between 2.551 and 2.6775 (2.55 * 1.05 = 2.6775) and between 2.549 and 2.4225 (2.55 * .95 = 2.4225).

If you're lucky enough to be working with a loose gemstone you may be able to get a specific gravity. If you can't nail it down accurately you can use the < or > sign. Example: if your stone floats in 2.67 liquid then you know its SG is less than 2.67. You can enter <2.67 in the Specific Gravity field. If it sinks in 2.67 liquid then you can enter >2.67. Note that you won't get any Near Hits using this method.

Transparency: Select the transparency from the drop-down list. Only those items on the list are in the database.

Phenomena: Select the phenomena from the drop-down list. Only those items on the list are in the database.

Pleochroism: Select the pleochroism from the drop-down list. Your only choices are 2 colors or 3 colors. You select the pleochroism Strength and colors from the next fields. A change has been made (by popular demand). Now, when the Pleochroism slider (see below) is on (to the right) the Separator will show all trichroic stones (3 Colors) when 2 Colors has been selected. Trichroic stones will show up on the Hits Table as Near Hits when 2 Colors is selected in Pleochroism. The gemstone name will change color and have a border around it. In the screen shot below you can see that four of the first five stones are trichroic.

Strength: Select the pleochroism strength from the drop-down list. If you can't decide on the strength just leave the field blank.

Polish Luster: Select the polish luster from the drop-down list. Polish luster is a range. Example: the gem diopside has a polish luster range from vitreous to resinous. That means if you enter vitreous, subvitreous, greasy or resinous you will get a match.

UV Long: Select the UV long wave property from the drop-down list. Only those items on the list are in the database.

UV Short: Select the UV short wave property from the drop-down list. Only those items on the list are in the database.

UV Colors (Fluorescence): Here you will be able select either a Longwave color, a Shortwave color or a Phosphorescence color. Note that you can also select Phosphorescence in general (without specifying a color). Select the color or colors that are the most dominant in your stone. For example, if your stone fluoresces stronger in the Shortwave lamp then use that color (this will increase your odds of reducing the Hit List). CAUTION: Colors are subjective and not all color combinations may be listed in the database. We think that most ID’s can be carried out without UV Colors but they’re here for you to use if you have a good match.

Hardness: Select the hardness number from the drop-down list. You can use the > and < signs. Example: You know your stone is fairly soft because of the multiple abrasions on the facet junctions. Being fairly sure the stone is less than 7 in hardness you can enter <7. This will return all stones that are 6.5 or less.

Magnification: This field really should be called Magnification and Visualization but we didn't have room. You will find all kinds of observations here such as "acrid odor to hot point," "air bubbles," or "black inclusions." While there are specific entries such as "platinum inclusions" we have tried to cross-reference these with more generic terms such as "metallic inclusions." Be aware that many of the more obscure gems have little or no data in this field because it isn't available. For that reason, use the Magnification field with care. If you get odd results that you are sure aren't accurate then don't use the Magnification field.

TIP: Some of the drop down lists are very long. To easily get to the term you are looking for, type the first couple of letters. Example: in Magnification you want to find "zebra stripe inclusions." Click the down arrow to open the drop down list. Then type the letter z and you are taken to the first item that starts with a z.

ERRORS: If you find (or suspect) any errors in either the gemstone database or in the search logic please email us at bwise@gemologytools.com

Below is an image of the bottom of the Gemstone table page where you will find Data and Photo buttons and buttons to start the Separator, the Inclusion Gallery and the Find Feature.

 

See also the Gemstone Database