gem recommendation online
First and foremost a Gemologist is not a Gemstone consultant for astrological purpose and does not recommend a lucky gemstone based on a Birth chart or for a specific objective such as good health, wealth etc.
A Gemologist is a person trained in identification, sorting, grading etc of a Gemstone and is in no way connected to Astrology etc.
There are two kinds of people who recommend Gemstones for astrological purpose.
Astrologers- They are plenty in number and each have their own unique methodology of gem recommendation. In majority of cases their information about Gemstones and quality etc is not upto mark. However some are quite good in suggestion of Gemstones as accurate remedial measures. To find a good one ,look for a body of work on the internet and look for good references.
Astro- Gemologist- This is a very rare breed even though now many wannabees lay claim wanting to belong to this category. This is a combination of excellence in both the categories of Astrology as well as Gemology and the AstroGemologist is the best positioned to make the most rewarding recommendation.
As stated earlier look for statistical body of work, evaluate work quality, look for references and you shall have your answer this since is a pretty limited range to choose from.